Mathematics High School

The amount of time a certain brand of light bulb lasts is normally distributed with a mean of 1800 hours and a standard deviation of 25 hours. Using the empirical rule, what percentage of light bulbs last between 1725 hours and 1875 hours?

Answers

Answer 1

Answer:

99.7%

Step-by-step explanation:

The empirical rule formula states that:

68% of data falls within 1 standard deviation from the mean - that means between μ - σ and μ + σ .

95% of data falls within 2 standard deviations from the mean - between μ – 2σ and μ + 2σ .

99.7% of data falls within 3 standard deviations from the mean - between μ - 3σ and μ + 3σ

Step 1

We have to find the number of standard deviations from the mean

μ = Mean = 1800 hours

σ = Standard deviation = 25 hours

For 1725 hours

μ - xσ =

1800 - 25x = 1725

25x = 1800 - 1725

25x = 75

x = 75/25

x = 3

For 1875 hours

1800 + 25x = 1875

25x = 1875 - 180

25x = 75

x = 75/25

x = 3

Step 2

From the above calculation, the bum of standard deviations from the mean is 3

Hence, the percentage of light bulbs last between 1725 hours and 1875 hours is 99.7%

Related Questions

How do I solve these problem?

Answers

Answer:

- 199

Step-by-step explanation:

a1 = 25

d = - 16

15th term is t15.

Formula : -

an = a + ( n - 1 )d

t15

= 25 + ( 15 - 1 ) - 16

= 25 + 14 ( - 16 )

= 25 + ( - 224 )

= 25 - 224

= - 199

Melissa built a square pyramid out of sand. The base of the pyramid has a side length of 18 centimeters. The height of the pyramid is 26
centimeters.
What is the volume of the pyramid?
A. 624 cm3
B. 1,872 cm
C. 2, 808 cm
D. 4,212 cm
E. 8, 424 cm

Answers

Answer:

C. 2, 808 cm^3

Step-by-step explanation:

Given that

The base of the pyramid is 18 centimeters

And, the height of the pyramid is 26 centimeters

We need to find out the volume of the pyramid

As we know that

The volume of the pyramid is

= 1 ÷ 3 × base^2 × height

= 1 ÷3 × 18^2 × 26

= 2,808 centimeter^3

Hence, the correct option is c.

Find the 93rd term of the arithmetic sequence -6,13,32...

Answers

Answer:

1742

Step-by-step explanation:

I am of the belief this is the right answer according to the arithmetic calculator.

P(blue) someone plz help me

Answers

what is the question¿

please help. solve for x. (i’ll give brainles if you help with all!

Answers

Answer:

Step-by-step explanation:

If I give you this helpful way to remember , can you solve these?

Use SOH CAH TOA to recall how the trig functions fit on a triangle

SOH: Sin(Ф)= Opp / Hyp

CAH: Cos(Ф)= Adj / Hyp

TOA: Tan(Ф) = Opp / Adj

or no?

HELP PLEASE!! a space station orbits earth at a rate of 57 miles every 3 seconds
Write the space stations rate of change

Answers

Answer:

i think its every 90 minutes but I could be wrong.

Step-by-step explanation:

PLS ILL MARK BRAINLIEST (100 points)

Answers

Answer:

For part A:

9x² - 36x + 36 = 0

9(x² - 4x + 4) = 0

9(x-2)(x-2) = 0

Radicand = Discriminant = 36² - 4(9)(36) = 0

there is 1 real zero that repeats itself)

zero is x=2.

Use factoring. Factors of 7 are 1 and 7

2x²-9x+7 = 0

(2x-7)(x-1) = 0

2x-7 = 0 (x-1)=0

2x = 7x=1

x = 7/2

Your solutions are x = 1 and x = 7/2

Step-by-step explanation:

Help ASAP on a timer ⏱

Answers

Answer:

B: 395

Step-by-step explanation:

Answer:400

Step-by-step explanation:

Can someone help I don’t understand

Answers

Answer:

8 hr

Step-by-step explanation:

8hr

hope this helps you!

i need help solving this math problem from my practice work

Answers

B is 27, your answer is 27

How big is a piece of A4 paper?

Answers

Answer:

210 x 297 mm

Hope that this helps!

Mandy the elephant weighs 7,390 lbs her baby luna weighs 1492 how many more pounds does mandy weigh than luna

Answers

Answer:

5898

Step-by-step explanation:

7,390 - 1,492 = 5898

HELP
Frank is making lemonade. He uses 12 lemons he brought from home and 10 lemons he asked Heidi to bring. He bought 5 bags
of lemons from the grocery store. Each bag holds the same number of lemons and he uses all of these. He uses 72 lemons
altogether. Which equation models the number of lemons, there are in each bag?
A 12 + 10 + 5 = 72.c
B 12x + 10x + 5 = 72x
C 12 + 10 + 5x = 72
D 12x + 10x + 5x = 72

Answers

I think that the promblem you should you is 12+10x+15

A company is testing a new protein shake which they claim works better than their existing brand in improving an athlete's performance. The company selected 60 athletes from a training camp database, and divided them into three groups. The ages for the groups were 16 to 20 years, 21 to 25 years, and 26 to 30 years. In each group, half of the subjects were asked to use the new protein shake for a month, and the other half were asked to use the company's existing brand for a month. The subjects were not informed about which protein shake they would be using. Which statements about this study are true? The study uses blocking to reduce variability from known factors. The study does not use a control group. The study uses random sampling. The study uses blocking on the basis of gender. The study uses a repeated measure design to reduce variability from unknown factors.

Answers

Answer:

The study uses random sampling

The study uses blocking to reduce variability from known factors

Step-by-step explanation:

Correct on Plato/Edmentum

Study uses blocking to reduce variability from know factor

and The study uses random sampling are the true statements

What is random sampling?

Random sampling is a part of the sampling technique in which each sample has an equal probability of being chosen

Here study uses blocking to reduce variability from know factor

The study uses random sampling

Hence, study uses blocking to reduce variability from know factor

and The study uses random sampling are the true statements

Learn more about Random sampling here

https://brainly.com/question/17238189

#SPJ2

Help please

Thanks <3

Answers

Answer:

answer in the screen shot provided

What is the distance between (-2,-8)(7,-3)

Answers

Answer:

[tex]\sqrt{106}[/tex] or 10.29563

Step-by-step explanation:

Use the distance formula to determine the distance between the two points.

[tex]d = \sqrt{(x_{2} -x_{1})^{2} + (y_{2} - x_{1})^{2} }[/tex]

d = distance

[tex](x_{1}, y_{1})[/tex] = coordinates of the first point

[tex](x_{2}, y_{2})[/tex] = coordinates of the second point

Answer:

[tex]\displaystyle d = \sqrt{106}[/tex]

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right

Algebra I

Coordinates (x, y)

Algebra II

Distance Formula: [tex]\displaystyle d = \sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]

Step-by-step explanation:

Step 1: Define

Identify

Point (-2, -8)

Point (7, -3)

Step 2: Find distance d

Simply plug in the 2 coordinates into the distance formula to find distance d

Substitute in points [Distance Formula]: [tex]\displaystyle d = \sqrt{(7--2)^2+(-3--8)^2}[/tex][√Radical] (Parenthesis) Subtract: [tex]\displaystyle d = \sqrt{(9)^2+(5)^2}[/tex][√Radical] Evaluate exponents: [tex]\displaystyle d = \sqrt{81+25}[/tex][√Radical] Add: [tex]\displaystyle d = \sqrt{106}[/tex]

question 9
9. Given ABCD
EFGH, find the length of GH.
A. 8
B. 7
C. 5
D. 10

Answers

Step-by-step explanation:

The Answer is B
I already take this question before

Find the value of each variable 17/ 18

Answers

Answer:

A) B.R(-9)?

Step-by-step explanation:

Answer:

17 - 42

18 - 50

Step-by-step explanation:

17)

You know the total measurement of both angles is 180.

So your formula is (2x+54) + x = 180. Now rearrange to get

180 - (2x+54) = x or 180-2x+54 =x

Simply to -2x+126 = x followed by moving x and moving 126 to get

-3x = -126 , now divide both sides by -3

18)

Your complete circle is 360 and you know one angle is 90.

Set your formula to 360=90+(3x)+(x-20)+(2x-10)

Rewrite to 360 = 90+3x+x-20+2x-10 and combine like terms

360 = 90 - 20 - 10 + 3x + x+2x

360 = 60 + 6x

360 - 60 = 6x

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