Answer:
x = 3/2 or 1.5
Step-by-step explanation:
All 5 of the quadratics are in standard form, whose general form is[tex]ax^2+bx+c[/tex]
One of the ways in which we solve quadratic equations is through the quadratic formula which is[tex]x=\frac{-b+/-\sqrt{b^2-4ac} }{2a}[/tex], where x is the root(s)
We can find the total number of solutions a quadratic equation has using the discriminant from the quadratic formula which is[tex]b^2-4ac[/tex]
When the discriminant is greater than 0, there is 2 distinct rootsWhen the discriminant is equal to 0, there is 1 distinct rootWhen the discriminant is less than 0, there are 0 distinct/"real" roots(a.) For 4x^2 + 16x - 9b, 4 is our a value, 16 is our b value and -9 is our c value:
[tex]16^2-4(4)(-9)\\256+144\\400 > 0[/tex]
(b.) For 2x^2 + 80x + 400, 2 is our a value, 80 is our b value, and 400 is our c value:
[tex]80^2-4(2)(400)\\6400-3200\\3200 > 0[/tex]
(c.) For x^2 - 6x - 9, 1 is our a value, -6 is our b value and -9 is our c value
Quick fact: for x^2 or -x^2, there's a 1 or -1 in front of the variable, but it's usually not written because it's a well known mathematical effect and it's assumed we already know this)[tex](-6)^2-4(1)(-9)\\36+36\\72 > 0[/tex]
(d.) For 4x^2 - 12x + 9, 4 is our a value, -12 is our b value, and 9 is our c value:
[tex](-12)^2-4(4)(9)\\144-144\\0=0[/tex]
We don't have to do (e.) because we see that since the discriminant for (d.) equals 0, this is the quadratic with only one distinct solution/rootWe can now solve for this root using the quadratic formula[tex]x=\frac{-(-12)+/-\sqrt{(-12)^2-4(4)(9)} }{2(4)}\\ \\x=\frac{12+/-\sqrt{0} }{8} \\\\x=12/8=3/2\\or\\x=1.5[/tex]
suppose n=6k + 1 prove that 12 | n^2 - 1.
My original answer was that 6*24=144
144+1=145
1452=21025
21025-1=21024
12/21024=1752.
My professor said I only proved it for one value. Can someone show me how to prove this for all values and explain please? I found one explanation but I cannot understand all the values and how they got some of their work. Thank you!
To prove that 12 | n^2 - 1 for all values where n = 6k + 1, we can use modular arithmetic.
First, let's simplify n^2 - 1:
n^2 - 1 = (6k + 1)^2 - 1
= 36k^2 + 12k
= 12(3k^2 + k)
So we need to show that 12 divides (3k^2 + k) for all values of k.
We can use modular arithmetic to prove this. Let's consider k modulo 3:
If k ≡ 0 (mod 3), then 3k^2 + k ≡ 0 (mod 3).
If k ≡ 1 (mod 3), then 3k^2 + k ≡ 4 (mod 3).
If k ≡ 2 (mod 3), then 3k^2 + k ≡ 2 (mod 3).
So in all cases, 3k^2 + k ≡ 0 (mod 3) or 3k^2 + k is divisible by 3.
Now let's consider k modulo 4:
If k ≡ 0 (mod 4), then 3k^2 + k ≡ 0 (mod 4).
If k ≡ 1 (mod 4), then 3k^2 + k ≡ 0 (mod 4).
If k ≡ 2 (mod 4), then 3k^2 + k ≡ 2 (mod 4).
If k ≡ 3 (mod 4), then 3k^2 + k ≡ 0 (mod 4).
So in all cases, 3k^2 + k is divisible by 4 if k is even, and if k is odd then 3k^2 + k is divisible by 2.
Therefore, 3k^2 + k is always divisible by 12, and so n^2 - 1 = 12(3k^2 + k) is always divisible by 12 when n = 6k + 1.
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Solve questions 1 through 5
The stereo system installer needs 170 ft of speaker wire.
How to calculate the valueIn this case, the two diagonals of the rectangular room are the longest sides of two right triangles. The length of one diagonal can be found by:
d1 = √(40² + 75²)
d1 = √(1600 + 5625)
d1 = √7225
d1 = 85 ft
Similarly, the length of the other diagonal is also 85 ft.
Total speaker wire = 2 × 85 ft = 170 ft
So, the stereo system installer needs 170 ft of speaker wire.
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Show your work or explain in complete sentences how to find Stephen's net income. Use the following information: Stephen earns $11 per hour at his job. Last month, Stephen worked for 32 hours. On his paycheck, Stephen noticed that he paid $37.30 for federal income tax, $21.82 for Social Security, and $5.10 for Medicare.
Stephen's net income is $287.78.
How to find Stephen's net income?
Stephen earns $11 per hour at his job and worked for 32 hours. The gross income (income before deduction) is:
gross income = 11 * 32 = $352
Stephen's net income is the money left afer deducting federal income tax, Social Security, and Medicare.
Net income = $352 - $37.30 - $21.82 - $5.10
Net income = $287.78
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A toy plane is thrown upward with an initial velocity of 7 meters per second from an initial height of 4 meters.
What is the maximum height of the plane?
A:6.5 meters
B:6.5 feet
C:0.7 meters
D:0.7feet
The maximum height of the toy plane is approximately 6.5 meters. Option A is correct.
The maximum height of the toy plane can be determined using the laws of motion and basic kinematics.
The equation for the height of the toy plane as a function of time, assuming no air resistance, can be represented by a quadratic equation in the form of;
h(t) = [tex]h_{0}[/tex] + [tex]V_{0}[/tex]t - (1/2)[tex]gt^{2}[/tex]
where; h(t) is the height of the plane at time t,
[tex]h_{0}[/tex] is the initial height (given as 4 meters),
[tex]V_{0}[/tex] is the initial velocity (given as 7 meters per second),
g is the acceleration due to gravity (which is approximately 9.8 m/s² on Earth), and
t is the time.
To find the maximum height of the plane, we need to determine the time at which the plane reaches its highest point. At this point, the vertical velocity of the plane becomes zero, before it starts to fall back to the ground.
The vertical velocity of the plane can be represented as;
[tex]V_{(t)}[/tex] = [tex]V_{0}[/tex] - [tex]g_{t}[/tex]
Setting v(t) to zero and solving for t, we get:
0 =[tex]V_{0}[/tex] - [tex]g_{t}[/tex]
[tex]g_{t}[/tex] = [tex]V_{0}[/tex]
t = [tex]V_{0}[/tex] / g
Substituting the given values for [tex]V_{0}[/tex] and g into the equation;
t = 7 m/s / 9.8 m/s²
t ≈ 0.714 seconds
So, the time taken for the toy plane to reach its highest point is approximately 0.714 seconds.
Now, we can substitute this value of t into the equation for h(t) to find the maximum height of the plane;
[tex]h_{(t)}[/tex] = [tex]h_{0}[/tex] + [tex]V_{0}[/tex] t - (1/2)[tex]gt^{2}[/tex]
[tex]h_{(t)}[/tex] = 4 m + 7 m/s × 0.714 s - (1/2) × 9.8 m/s² × (0.714 s)²
Calculating the above expression, we get:
[tex]h_{(t)}[/tex] ≈ 6.46 meters
Therefore, the maximum height of the toy plane is near by 6.5 meters.
Hence, A. is the correct option.
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8.3.23. true or false: if a is a complete upper triangular matrix, then it has an upper triangular eigenvector matrix s.
The answer is: True. When matrix A is upper triangular, its eigenvalues are located on its main diagonal. If you find the eigenvectors corresponding to each eigenvalue, you can construct an eigenvector matrix S.
An upper triangular matrix is a square matrix in which all entries below the main diagonal are zero. An eigenvector of a matrix A is a nonzero vector x such that Ax is a scalar multiple of x. That is, there exists a scalar λ such that Ax = λx.
For a complete upper triangular matrix, all of its eigenvalues are on the diagonal. To see this, consider the characteristic polynomial of a complete upper triangular matrix:
p(λ) = det(A - λI)
where I is the identity matrix. Since A is upper triangular, its determinant is the product of its diagonal entries, and det(A - λI) is a polynomial of degree n (the size of the matrix) in λ. Therefore, there are n roots of p(λ), which correspond to the eigenvalues of A. Since A is completely upper triangular, all of its eigenvalues are on the diagonal.
Now, let's consider the eigenvector matrix S of A. This is a matrix whose columns are the eigenvectors of A. Since A is upper triangular, any eigenvector of A must also be upper triangular (or zero). Therefore, the eigenvector matrix S must also be upper triangular. In summary, if a is a complete upper triangular matrix, then all of its eigenvalues are on the diagonal, and its eigenvector matrix S is upper triangular. Therefore, the statement is true.
"If A is a complete upper triangular matrix, then it has an upper triangular eigenvector matrix S." When a matrix A is upper triangular, its eigenvalues are located on its main diagonal. If you find the eigenvectors corresponding to each eigenvalue, you can construct an eigenvector matrix S. Since A is upper triangular, the eigenvector matrix S will also be upper triangular.
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answer all boxes and read the questions
The area of the lateral face of cylinder = 150.79 ft²
The area of the two bases of the cylinder = 56.55 ft²
The total surface area of the cylinder = 207.34 ft²
We know that the formula for the surface area of cylinder is:
A = 2πrh + 2πr²
where r is the radius of the cylinder
and h is the height of the cylinder
Here, r = 3 ft and h = 8 ft
The area of the lateral face of cylinder would be,
A₁ = 2 × π × r × h
A₁ = 2 × π × 3 × 8
A₁ = 48 × π
A₁ = 150.79 sq. ft.
And the area of two bases is,
A₂ = 2πr²
A₂ = 2 × π × 3²
A₂ = 18 × π
A₂ = 56.55 sq. ft.
The total surface area of cylinder would be,
A = A₁ + A₂
A = 150.79 + 56.55
A = 207.34 sq. ft.
Therefore, the required surface area of cylinder = 207.34 ft²
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exercise 1 find the surface area of the surface parametrized (and graphed) by the following commands. (you will need to cut and paste before you can evaluate them.) f[s , t ]
The surface area of a surface parametrized by a function f(s, t), we use the formula:
Surface Area = ∫∫ √[f_s(s,t)^2 + f_t(s,t)^2 + 1] ds dt
The formula above calculates the surface area by integrating the square root of the sum of the squares of the partial derivatives of f with respect to s and t, plus one, over the surface.
Essentially, the formula is finding the magnitude of the gradient of the surface, which gives the rate of change of the surface in all directions.
Surface Area = ∫∫ √[f_s(s,t)^2 + f_t(s,t)^2 + 1] ds dt
The surface area formula can be used to find the surface area of various types of surfaces, such as parametric surfaces, implicit surfaces, and surfaces of revolution.
However, the integration required to evaluate the formula can be quite challenging, especially for complex surfaces. In such cases, numerical methods may be used to approximate the surface area.
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What is the Y-coordinate of the
point that partitions segment AC
into a 1:2 ratio?
10
9
8
7
6
5
4
3
2
1
A
2 3
5
9
с
7 8
00
The Y-coordinate would be:
B
10
x
The y-coordinate of the point that partitions segment AC into a 1:2 ratio is given as follows:
y = 5.
How to obtain the y-coordinate?The y-coordinate of the point that partitions segment AC into a 1:2 ratio is obtained applying the proportions in the context of the problem.
The segment AC is partitioned into a 1:2 ratio, hence the equation for the coordinates of P are given as follows:
P - A = 1/3(C - A).
The coordinates of A and C are given as follows:
A(1,3) and C(6,9).
Hence the y-coordinate of B is obtained as follows:
y - 3 = 1/3(9 - 3)
y - 3 = 2
y = 5.
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How to solve a problem
In a PivotTable, you can group data by _______ field typescalculated or filtereddate or numberlogical parameters or textincremental or value
In a PivotTable, you can group data by date or number field types. To do this, follow these steps:
1. Select your PivotTable by clicking on any cell within it.
2. Choose the date or number field you want to group.
3. Right-click the selected field and click "Group" from the context menu.
4. In the Grouping dialog box, specify the grouping options based on your preferences (e.g., grouping by months, years, or specific intervals).
5. Click "OK" to apply the grouping.
Please note that grouping data by calculated, filtered, logical parameters, text, incremental, or value field types is not directly supported in a PivotTable.
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solve m^4 =625
m= +156.5
m= +5
m cannot be found
m= +125
Please look at picture
Answer:
m = +/- 5
Step-by-step explanation:
We can solve the equation by taking the fourth root of both sides.
[tex]+/-\sqrt[4]{m^4}=+/-\sqrt[4]{625} \\m=5\\m=-5[/tex]
(5)(5)(5)(5) = 625
(-5)(-5)(-5)(-5) = 625
The +/- in the answers come from the fact that whenever you have a even exponent (e.g., x^2 or m^4), you always get a positive answer, even if the base you're raising to the particular exponent is negative
What value of x will make M the midpoint of PO if PM-3x-1 and PQ-5x+3?
The value of x that would make M the midpoint of PQ if PM = 3x-1 and PQ = 5x+3 include the following: 2.
How to determine the midpoint of a line segment?In Mathematics, the midpoint of a line segment with two end points can be calculated by adding each end point on a line segment together and then divide by two (2).
Since M is the midpoint of line segment PO, we have the following:
Line segment PM = Line segment PQ
3x - 1 = 5x + 3
5x - 3x = 3 + 1
2x = 4
x = 4/2
x = 2
PM = 3x - 1 = 3(2) - 1 = 6 - 1 = 5 units.
PQ = 5x + 3 = 5(2) + 3 = 10 + 3 = 13 units.
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suppose the length, in words, of the essays written for a contest are normally distributed and have a known population standard deviation of 325 words and an unknown population mean. a random sample of 25 essays is taken and gives a sample mean of 1640 words. identify the parameters needed to calculate a confidence interval at the 98% confidence level. then find the confidence interval. z0.10 z0.05 z0.025 z0.01 z0.005 1.282 1.645 1.960 2.326 2.576 you may use a calculator or the common z values above. round all numbers to three decimal places, if necessary.
The 98% confidence interval for the population mean is (1473.06, 1806.94).
The parameters needed to calculate a confidence interval are:
Sample mean (x) = 1640
Population standard deviation (σ) = 325
Sample size (n) = 25
Confidence level = 98%
To find the confidence interval, we can use the formula:
CI = x ± z*(σ/√n)
where z* is the z-score associated with the desired confidence level.
Since the confidence level is 98%, we need to use the z-score associated with a tail probability of 0.01 (0.5% on each tail). From the table given, this is z0.005 = 2.576.
Substituting the values, we get:
CI = 1640 ± 2.576*(325/√25) = 1640 ± 166.94
Therefore, the 98% confidence interval for the population mean is (1473.06, 1806.94).
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Which of the following is the function for the graph below?
The function graphed is defined as follows:
y = -2(x - 2)² + 3.
How to obtain the equation of the parabola?The equation of a parabola of vertex (h,k) is given by the equation presented as follows:
y = a(x - h)² + k.
In which a is the leading coefficient.
The coordinates of the vertex in this problem are given as follows:
(2,3).
Hence the parameters are h = 2 and k = 3, thus:
y = a(x - 2)² + 3
When x = 0, y = -5, hence the leading coefficient a is obtained as follows:
-5 = 4a + 3
4a = -8
a = -2.
Thus the equation is:
y = -2(x - 2)² + 3.
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helpppppp!! The mass of a car is 1990 kg rounded to the nearest kilogram. The mass of a person is 58.7 kg rounded to 1 decimal place. Write the error interval for the combined mass, m , of the car and the person in the form a ≤ m < b
Answer:
The mass of the car rounded to the nearest kilogram is 1990 kg, which has an error interval of 1989.5 kg ≤ car mass < 1990.5 kg.
The mass of the person rounded to 1 decimal place is 58.7 kg, which has an error interval of 58.65 kg ≤ person mass < 58.75 kg.
To find the error interval for the combined mass, we need to add the lower and upper bounds of the two intervals:
1989.5 kg + 58.65 kg = 2048.15 kg
1990.5 kg + 58.75 kg = 2049.25 kg
Therefore, the error interval for the combined mass, m, of the car and the person is: 2048.15 kg ≤ m < 2049.25 kg
Answer:
To find the error interval for the combined mass of the car and the person, we need to consider the possible maximum and minimum values for the masses.
For the car, since it is rounded to the nearest kilogram, the actual mass could be anywhere between 1989.5 kg and 1990.5 kg.
For the person, since it is rounded to 1 decimal place, the actual mass could be anywhere between 58.65 kg and 58.75 kg.
To find the maximum and minimum combined masses, we add the maximum possible mass of the car (1990.5 kg) to the maximum possible mass of the person (58.75 kg) and we add the minimum possible mass of the car (1989.5 kg) to the minimum possible mass of the person (58.65 kg):
Maximum combined mass = 1990.5 kg + 58.75 kg = 2049.25 kg
Minimum combined mass = 1989.5 kg + 58.65 kg = 2048.15 kg
Therefore, the error interval for the combined mass, m, of the car and the person is:
2048.15 kg ≤ m < 2049.25 kg
The square below has an area of
�
2
−
12
�
+
36
x
2
−12x+36x, squared, minus, 12, x, plus, 36 square meters.
What expression represents the length of one side of the square?
An expression that represents the length of one side of the square is √(12x/35).
How to calculate the area of a square?In Mathematics and Geometry, the area of a square can be calculated by using this mathematical equation (formula);
A = x²
Where:
A represents the area of a square.x represents the side length of a square.By substituting the given parameters into the formula for the area of a square, we have the following;
-12x + 36x² = x²
36x² - x² = 12x
35x² = 12x
x = √(12x/35)
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Solve using elimination. 10x + 8y = 12 4x + y = –15 ( , )
Answer:
x = -6
Step-by-step explanation:
you have given
10x + 8y = 12 and 4x + y = -15
so you must put the one var. x or y by same cofficent and in opposite sighn
so 10x + 8y = 12
- 8 (4x + y = -15 ) ......... i multiplied by -8
10x + 8y = 12
-32x - 8y = 120
then you will add the equation
(10x + 8y) + (-32x - 8y) = 12 + 120
afeter you simlify it u will get
-22x = 132
-22x = 132
x = -6 .... by dividing both sides by -22
Answer:
(-6,9)
Step-by-step explanation:
Multiply 4x + y = -15 all the say through by -8 and then add to 10x + 8y = 12
-32x -8y = 120
10x + 8y = 12
-22x = 132 Divide both sides by -22
x = -6
Substitute -6 for x
4x + y = -15
4(-6) + y = -15
-24 + y = -15 Add 24 to both sides
y = 9
Check
10x + 8y = 12
10(-6) + 8(9) = 12
-60 + 72 = 12
12 = 12 checks
4x + y = -15
4(-6) + 9 = -15
-24 + 9 = -15
-15 = -15 Checks.
Helping in the name of Jesus.
The manager has 20 welders available. Calculate the number of frames they will complete in 4 hours.
The number of frames that the welders would be able to complete in 4 hours would be 10 frames.
How to find the number of frames ?The time taken by one welder is 8 hours for one frame which means the work rate would be:
= 1 / 8
= 1 / 8 frames per hour
If we have 20 welders therefore, the work rate per hour would be :
= 1 / 8 x 20
= 2. 5 frames per hour
Given 4 hours, the number of frames they would make is:
= 2. 5 x 4 hours
= 10 frames
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First part of question is:
A welding company produces burglar frames for windows and doors. In order to complete one frame, one welder needs 8 hours.
please show all workExpress the following in degrees only. Be sure to use the decimal form. a. 39°50¢ a) b. 42°35¢ b) c. 15°20€ c) d. 1°59€ d) Convert the following from arc units into time units: a. 28°49€
28°49€ arc unit into time is approximately 1.867 hours.
We'll convert the given angles from degrees, minutes, and seconds (or cents and euros as placeholders) to degrees in decimal form. Then, we'll convert the angle from arc units to time units.
a) 39°50¢
To convert 50¢ to degrees, divide by 60 (since 1 degree = 60 minutes):
50¢ / 60 = 0.8333 (rounded to four decimal places)
So, 39°50¢ in decimal form is:
39 + 0.8333 = 39.8333°
b) 42°35¢
To convert 35¢ to degrees:
35¢ / 60 = 0.5833 (rounded to four decimal places)
So, 42°35¢ in decimal form is:
42 + 0.5833 = 42.5833°
c) 15°20€
To convert 20€ to degrees (1 degree = 3600 seconds):
20€ / 3600 = 0.0056 (rounded to four decimal places)
So, 15°20€ in decimal form is:
15 + 0.0056 = 15.0056°
d) 1°59€
To convert 59€ to degrees:
59€ / 3600 = 0.0164 (rounded to four decimal places)
So, 1°59€ in decimal form is:
1 + 0.0164 = 1.0164°
Now, we'll convert 28°49€ from arc units to time units:
28°49€ = 28 + (49 / 3600) = 28.0136° (in decimal form)
To convert degrees to time units, multiply by 24 (since there are 24 hours in a day) and divide by 360 (since there are 360 degrees in a circle):
28.0136° * (24 / 360) = 1.867 (rounded to three decimal places)
So, 28°49€ in time units is approximately 1.867 hours.
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I do not know what is -4x + 8 = 42
Answer:
-8.5
Step-by-step explanation:
First we need to get the -4x by it self which means moving the 8 so what we need to do is subtract 8 from its self and what we do on one side we do to the other so 42-8=34 then the last thing to do is just divided 34 divided by -4 and we get
-8.5 as the answer.
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What is the value of M?
Answer:
44 degrees
Step-by-step explanation:
To solve this problem you can subtract 70 by 26. You can do this because those two angles add to the more significant angle. Therefore, to solvr this all you have to do is subtract 70-26. Doing so gives you your answer of 44 degrees
How many blocks are needed to complete the full cube
The number of blocks needed to complete the big or full cube depends on size of cube. So, number of blocks required to complete it equals to 45.
A cube is a three-dimensional geometry, which may be solid or hollow and containing six equal squares. According to the shape of the cube, we can make a cube from any cubes. Now look at the cube image above. There is one more layer of blocks to fill in because the blocks are still 5 blocks by 4 blocks (not make a cube). We need to add another 25 blocks at the top to meet the cube definition. Some times we would often just count the missing blocks which is 20 here but after adding all 20 blocks in figure still it isn't a cube. So, 20 is wrong because the sides won’t be equal. The width and the length is made of 5 blocks but the height is just four blocks. So, it's need to add another 25 blocks the top to make it a cube. Hence, the correct answer is 45.
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Complete question:
The above figure complete the question.
How many blocks are needed to complete the full cube ?
The average number of cavities that 30-year-old Americans have had in their lifetimes is 11. The standard deviation 2.7 cavities. Do 20 year olds have more cavities? The data show the results of a survey of 16 twenty-year-olds who were asked how many cavities they have had. Assume that that distribution of the population is normal.
6, 7, 7, 8, 7, 8, 9, 6, 5, 6, 7, 8, 7, 6, 9, 8
What can be concluded at the 0.05 level of significance?
H0:mu.gif= 7
Ha:mu.gif[ Select ] ["<", "Not Equal to", ">"] 7
Test statistic: [ Select ] ["F", "t", "Chi-square", "Z"]
p-Value = [ Select ] ["0.063", "0.427", "0.126", "0.032"] . Round your answer to three decimal places.
[ Select ] ["Fail to reject the null hypothesis", "Reject the null hypothesis"]
Conclusion: There is [ Select ] ["sufficient", "insufficient"] evidence to make the conclusion that the population mean number of cavities for 20-year-olds is more than 11
Show transcribed image text
We do not have sufficient evidence to conclude that 20-year-olds have more cavities than 30-year-olds.
First, we need to calculate the sample mean and standard deviation of the given data:
x = (6+7+7+8+7+8+9+6+5+6+7+8+7+6+9+8)/16 = 7
s = sqrt((Σ(x - x)²)/(n-1)) = sqrt((Σ(x²) - n(x)²)/(n-1)) = 1.247
Now, we can set up the hypothesis test:
H0: μ = 7 (20-year-olds have the same average number of cavities as 30-year-olds)
Ha: μ > 7 (20-year-olds have more cavities than 30-year-olds)
We will use a t-test since the population standard deviation is unknown and we have a small sample size (n = 16). The test statistic is:
t = (x - μ) / (s/sqrt(n)) = (7 - 7) / (1.247/sqrt(16)) = 0
The degrees of freedom is n-1 = 15. Using a t-table with α = 0.05 and df = 15, we find the critical value to be 1.753.
The p-value is the probability of getting a t-value as extreme or more extreme than the calculated t-value under the null hypothesis. Since our null hypothesis is that μ = 7 and our alternative hypothesis is that μ > 7, we have a one-tailed test. Using a t-table with df = 15, we find the p-value to be 0.5.
Since our p-value (0.5) is greater than α (0.05), we fail to reject the null hypothesis. We do not have sufficient evidence to conclude that 20-year-olds have more cavities than 30-year-olds.
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measurements of water quality were taken from a river downstream from an abandoned chemical dumpsite. concentrations of a certain chemical were obtained from 9 measurements taken at the surface of the water, 9 measurements taken at mid-depth of the water, and 9 measurements taken at the bottom of the water. what type of study was conducted, and what is the response variable of the study? responses an experiment was conducted, and the response variable is the concentration of the chemical.
Answer:
The type of study conducted is an observational study. The response variable of the study is the concentration of the chemical.
the estimated resale value (in dollars) of a company car after years is given by 23,351 0.783 . what is the rate of depreciation (in dollars per year) after 2 years? round to the nearest cent. the car is depreciating at $ per year. note: the rate of depreciation is |r'(t)|. your answer should be positive.
To find the rate of depreciation after 2 years, we need to find the derivative of this function at t = 2.
V(t) = 23,351(0.783)^t
V'(t) = 23,351(0.783)^t * ln(0.783) [Using the chain rule]
V'(2) = 23,351(0.783)^2 * ln(0.783) ≈ -2,346.29
Since we are interested in the absolute value of the rate of depreciation, we can ignore the negative sign. Therefore, the car is depreciating at $2,346.29 per year (rounded to the nearest cent).
Note that this is the instantaneous rate of depreciation at t = 2. The average rate of depreciation over the first two years would be the difference in resale value divided by the number of years, which would be:
[(23,351(0.783)^2) - 23,351] / 2 ≈ $2,336.67 per year
Hi! To find the rate of depreciation after 2 years, we need to first determine the resale value of the car after 2 years and then find the difference in value per year. Here's a step-by-step explanation:
1. Plug in the given years (t=2) into the formula for the estimated resale value: V(t) = 23,351(0.783^t)
2. Calculate the resale value after 2 years: V(2) = 23,351(0.783^2) ≈ 14,342.76 (rounded to the nearest cent)
3. Find the depreciation value by subtracting the resale value from the initial value: Depreciation = Initial Value - Resale Value = 23,351 - 14,342.76 ≈ 9,008.24
4. Calculate the rate of depreciation per year: Rate of Depreciation = Depreciation / Years = 9,008.24 / 2 ≈ 4,504.12
The car is depreciating at approximately $4,504.12 per year after 2 years, rounded to the nearest cent.
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What is the y-intercept of the function f(x)= -4(6)^x +1
a) (0, 1)
b) (0, -3)
c) (-4, 0)
d) (-0.774, 0)
Econ112 (Stats for Econ & Bus) - Tutorial 4 Assessment To be submitted to on CANVAS, 9am Monday 25th April. Standard late penalties apply. However, any work received after the tutorial seminar starts will receive a mark of zero as solutions are discussed here. [Any technical problems hard copy submissions must be resolved via help-ticket to CSD] ALL questions are worth 1 Mark. SECTION A (C.I. & Hypothesis-Test with known 0 - see lectures week 8) [6 Marks] Question 1 The business model for flying in the USA tends to be towards a 'base' pricing model with additional ch arges for flight options, including baggage checking(!) Nine American airlines were selected at rando m. For each airline, the current fee for checking a single bag was recorded. The average for these 9 airlines is x = $25. Assume that the current fee follows a normal distribution with unknown mean u an d standard deviation o = - $6. = A 90% confidence interval for p is: A) $25 + $6.00 B) $25 + $3.29 C) $25 + $3.92
D) $25 + $9.87 E) $25 + $11.76
The 90% confidence interval for the average fee for checking a single bag is $21.71 to $28.29, which corresponds to option B) $25 + $3.29
To calculate a 90% confidence interval for the average fee for checking a single bag.
To calculate a 90% confidence interval, we need the sample mean (X), the standard deviation (σ), and the sample size (n). From your question, we have:
X = $25
σ = $6
n = 9
Since we know the standard deviation, we can use the z-score for a 90% confidence interval, which is 1.645 (you can find this in a standard z-table).
Next, we need to calculate the standard error (SE), which is the standard deviation divided by the square root of the sample size:
[tex]SE=\frac{σ}{\sqrt{n} }[/tex]
[tex]SE= \frac{ 6}{\sqrt{9} }[/tex]
[tex]SE= \frac{ 6}{3 }[/tex]
SE = $2
Now, multiply the z-score by the standard error:
Margin of Error (ME) = 1.645 × SE
ME = 1.645 × $2
ME = $3.29
Finally, construct the 90% confidence interval by adding and subtracting the margin of error from the sample mean:
Lower Limit: X - ME = $25 - $3.29 = $21.71
Upper Limit: X + ME = $25 + $3.29 = $28.29
Thus, the 90% confidence interval for the average fee for checking a single bag is $21.71 to $28.29, which corresponds to option B) $25 + $3.29.
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What is the value of x in the equation 4.76 - (23 x*51)-1(-33x+1):
The required value of x in the given equation is -0.00047.
Let's first simplify the expression inside the parentheses:
-33x+1 = 1-33x
Now, we can substitute this back into the original equation and use order of operations (PEMDAS) to simplify:
4.76 - (23 x 51)-1(-33x+1) = 4.76 - (23/51)(1-33x)
= 4.76 - (23/51) + (23/17)x
Now, we want to solve for x. We'll start by isolating the term with x on one side of the equation:
(23/17)x = 4.76 - (23/51)
x =-0.00047
Therefore, the value of x in the given equation is -0.00047.
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Amaya used these steps to solve the equation 8x+4=9+4(2x−1)
. Which choice describes the meaning of her result, 4=5?
the choices are :
Amaya made a mistake because 4
is not equal to 5
.
No values of x
make the equation true.
.
All values of x
make the equation true.
.
The solution is x=4
or 5
.
Amaya made a mistake because 4 is not equal to 5. She incorrectly wrote 4=5 in the final step of solving the equation 8x+4=9+4(2x-1). So, the correct answer is A).
In step 1, Amaya sets up the equation 8x+4=9+4(2x-1).
In step 2, she simplifies the right side of the equation to 9+8x-4=5+8x.
In step 3, she subtracts 8x from both sides of the equation to get 4=5.
In step 4, she simplifies the equation to 4=9-4.
In step 5, she mistakenly writes that 4=5, which is incorrect.
Therefore, the correct choice is that Amaya made a mistake because 4 is not equal to 5. So, the correct option is A).
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Sam had four math tests last month. His scores were 81, 94, 83, and 91. What is the median of his scores?
Answer:
87
Step-by-step explanation:
first you need to know the median is the middle of the data set.
so 81, 83, 91, 94 the middle is 83 and 91 but you match inbetween both of those so the answer would be 87.
Hope this helps!! good luck