Below are two parallel lines with a third line intersecting them.

A study of the amount of time it takes a mechanic to rebuild the transmission for a 1992 Chevrolet Cavalier shows that the mean

Dovator [93]

Answer:

B) 0.0069

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution

Problems of normally distributed samples are 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:

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

The Z-score measures how many standard deviations the measure is from the mean. 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, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

In this question, we have that:

$\mu = 8.4, \sigma = 1.8, n = 40, s = \frac{1.8}{\sqrt{40}} = 0.2846$

Find the probability that their mean rebuild time exceeds 9.1 hours.

This is 1 subtracted by the pvalue of Z when X = 9.1. So

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

By the Central Limit Theorem

$Z = \frac{9.1 - 8.4}{0.2846}$

$Z = 2.46$

$Z = 2.46$ has a pvalue of 0.9931

1 - 0.9931 = 0.0069

So the answer is B.

6 0

3 years ago

FInd the sum of the first 20 terms of the series 3+5+7+....?

melamori03 [73]

Answer:

B.) 440

Explanation:

I added everything together.

3 0

2 years ago

Of the 650 students at west more junior high,4% will receive a perfect attendance award. How many students will receive a perfec

jolli1 [7]

Answer:

26 students

Step-by-step explanation:

4% of 650 is 26

5 0

3 years ago

Read 2 more answers

plz help me now plz: A cable 65 meters long is cut into two pieces so that one piece is 18 meters longer than the other. Find th

GalinKa [24]

Answer:

One piece is 23.5

the other is 41.5

Step-by-step explanation:

first subtract 18 from 65 that will give you 47. Then 47÷2= 23.5. this is the length of the shorter piece. since one piece is 18 m longer then the other, add 18 to 23.5. that will give you the length of the longer piece. You can check your work by adding 23.5 and 41.5. They equal 65.

6 0

3 years ago

keiko david and tony have a total of 106$ in their wallets. david has $6 less than keiko tony has 2 times what david has. how mu

mafiozo [28]

<h3>Answer:</h3>

Keiko have $31 in her wallet.

David have $25 in his wallet.

Tony have $50 in his wallet.

<h3>Step-by-step explanation:</h3>

Keiko

Let x = the amount in Keiko’s wallet.

David

David has $6 less than Keiko .

x - 6

Tony

Tony has has two times what David has.

2(x - 6)

The total sum of their money = 106

Keiko

x + x - 6 + 2(x - 6) = 106

2x - 6 + 2x - 12 = 106

4x - 18 = 106

4x = 106 + 18

4x /4 = 124/4

x = 31

Therefore Keiko have $31 in her wallet.

David

x - 6

31 - 6 = 25

Therefore David have $25 in his wallet.

Tony

2(x - 6)

2(31 - 6)

2(25) = 50

Therefore Tony have $50 in his wallet.

To check your work out

31 + 25 + 50 = 106

4 0

2 years ago