The list below shows all of the possible outcomes for flipping four coins.

Many, many snails have a one-mile race, and the time it takes for them to finish is approximately normally distributed with mean

Natali [406]

Answer:

The percentage of snails that take more than 60 hours to finish is 4.75%

The relative frequency of snails that take less than 60 hours to finish is .9525

The proportion of snails that take between 60 and 67 hours to finish is 4.52 of 100.

There is a 0% probability that a randomly chosen snail will take more than 76 hours to finish.

To be among the 10% fastest snails, a snail must finish in at most 42.26 hours.

The most typical of 80% of snails that between 42.26 and 57.68 hours to finish.

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by

$Z = \frac{X - \mu}{\sigma}$

After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X.

In this problem, we have that:

Many, many snails have a one-mile race, and the time it takes for them to finish is approximately normally distributed with mean 50 hours and standard deviation 6 hours.

This means that $\mu = 50$ and $\sigma = 6$ .

The percentage of snails that take more than 60 hours to finish is %

The pvalue of the zscore of $X = 60$ is the percentage of snails that take LESS than 60 hours to finish. So the percentage of snails that take more than 60 hours to finish is 100% substracted by this pvalue.

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{60 - 50}{6}$

$Z = 1.67$

A Zscore of 1.67 has a pvalue of .9525. This means that there is a 95.25% of the snails take less than 60 hours to finish.

The percentage of snails that take more than 60 hours to finish is 100%-95.25% = 4.75%.

The relative frequency of snails that take less than 60 hours to finish is

The relative frequence off snails that take less than 60 hours to finish is the pvalue of the zscore of X = 60.

In the item above, we find that this value is .9525.

So, the relative frequency of snails that take less than 60 hours to finish is .9525

The proportion of snails that take between 60 and 67 hours to finish is:

This is the pvalue of the zscore of X = 67 subtracted by the pvalue of the zscore of X = 60. So

$X = 67$

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{67 - 50}{6}$

$Z = 2.83$

A zscore of 2.83 has a pvalue of .9977.

For X = 60, we have found a Zscore o 1.67 with a pvalue of .9977

So, the percentage of snails that take between 60 and 67 hours to finish is:

$p = .9977 - 0.9525 = .0452$

The proportion of snails that take between 60 and 67 hours to finish is 4.52 of 100.

The probability that a randomly-chosen snail will take more than 76 hours to finish (to four decimal places)

This is 100% subtracted by the pvalue of the Zscore of X = 76.

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{76 - 50}{6}$

$Z = 4.33$

The pvalue of Z = 4.33 is 1.

So, there is a 0% probability that a randomly chosen snail will take more than 76 hours to finish.

To be among the 10% fastest snails, a snail must finish in at most hours.

The most hours that a snail must finish is the value of X of the Zscore when p = 0.10.

Z = -1.29 has a pvalue of 0.0985, this is the largest pvalue below 0.1. So what is the value of X when Z = -1.29?

$Z = \frac{X - \mu}{\sigma}$

$-1.29 = \frac{X - 50}{6}$

$X - 50 = -7.74$

$X = 42.26$

To be among the 10% fastest snails, a snail must finish in at most 42.26 hours.

The most typical 80% of snails take between and hours to finish.

This is from a pvalue of .1 to a pvalue of .9.

When the pvalue is .1, X = 42.26.

A zscore of 1.28 is the largest with a pvalue below .9. So

$Z = \frac{X - \mu}{\sigma}$

$1.28 = \frac{X - 50}{6}$

$X - 50 = 7.68$

$X = 57.68$

The most typical of 80% of snails that between 42.26 and 57.68 hours to finish.

5 0

3 years ago

Write an equation for a line containing (-8,12) that is parallel to the line containing the points (3,2) and (-7,2)

jarptica [38.1K]

First we need to find the slope.

slope = (y2 - y1) / (x2 - x1)

slope = (-5 - 2) / (5 - -3)

slope = (-7) / (5 + 3)

slope = -7/8

.

Point-slope form:

y - y1 = m(x - x1)

y - 2 = (-7/8)(x - -3)

y - 2 = (-7/8)(x + 3)

y - 2 = (-7/8)x - 21/8

y = (-7/8)x - 21/8 + 2

y = (-7/8)x - 21/8 + 16/8

y = (-7/8)x - 5/8

6 0

3 years ago

Read 2 more answers

A rectangular cardboard has dimensions as shown. The length of the cardboard can be found by dividing its area by its width. Wha

Annette [7]

Answer:

45678

Step-by-step explanation:

A rectangular cardboard has dimensions as shown. The length of the cardboard can be found by dividing its area by its width. What is the length of the cardboard in inches?

Rectangle with width labeled on the right, width equals 4 and 1 over 4 inches. Below the rectangle, it says, length equals question mark. Inside the rectangle, it says, area equals 41 and 2 over 3 square inches.

9 and 41 over 51

10 and 1 over 4

36 and 5 over 6

174 and 29 over 48

help asap

8 0

2 years ago

I need help with this <br><br> look at picture <br><br> Complementary angles

Gwar [14]

Answer:

x is equal to 11...........

4 0

2 years ago

Read 2 more answers

The diameter of a sphere is measured to be 4.17 in.

gtnhenbr [62]

Step-by-step explanation:

To find the radius of the sphere we must convert the inches to centimeters

Using the conversation

1 inch = 2.54 cm

If 1 inch = 2.54 cm

4.17 inch = 2.54 × 4.17 = 10.59 cm

We can find the radius using the formula

$radius = \frac{diameter}{2}$

From the question

diameter = 10.59 cm

So we have

$radius = \frac{10.59}{2}$

<h3>radius = 5.30 cm</h3>

Surface area of a sphere= 4πr²

where

r is the radius

Surface area = 4(5.30)²π

= 112.36π

= 352.989

We have the answer as

<h3>Surface area = 353 cm²</h3>

Volume of a sphere is given by

$\frac{4}{3} \pi {r}^{3}$

r = 5.30

The volume of the sphere is

$\frac{4}{3} ( {5.30})^{3} \pi$

= 623.61451

We have the answer as

<h2>Volume = 623.6 cm³</h2>

Hope this helps you

3 0

3 years ago