1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
kotykmax [81]
3 years ago
10

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

is 8.4 hours and the standard deviation is 1.8 hours. If 40 mechanics are randomly selected, find the probability that their mean rebuild time exceeds 9.1 hours.
A ) 0.1046 B) 0.0069 C ) 0.1285 D ) 0.0046
Mathematics
1 answer:
Dovator [93]3 years ago
6 0

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.

You might be interested in
Please answer I’ll rate brainlyest
Dafna1 [17]

Answer:

54.1%

Step-by-step explanation:

From the table, the total number of patients with type-B blood is given as 183. On the other hand, the number of males with type-B blood is given as 99. The percentage of patients with type-B blood who are males can be calculated as;

(the number of males with type-B blood/the total number of patients with type-B blood) * 100%;

( 99/183) * 100 = 54.1%

Therefore, the percentage of patients with type-B blood who are males is 54.1

7 0
3 years ago
Joel can either work 2 days for 11 hours each day or 4 days for 6 hours each day. He takes the bus for $2.25 each way. On days h
Oxana [17]
Joel's work makes $9.50/ hr. During the 2 Day, 11 hrs shift, he earns a total of $217.55 but spends a cash of $9 on his bus. Therefore, the money left is $208.55. While on his 4 day, 6 hrs shift, he earns a total of $228 but spends $18, with a total money of $210. The option that he should take to make the most money is the 4 days for 6 hrs shift. 
7 0
3 years ago
PLEASE HELP IN ONE MINUTE
Marysya12 [62]

Answer:

i wish i could help but its kind of over a minute but the answer is C

6 0
2 years ago
Two percent of half a number is 5. What is the number ?
Anika [276]

Answer:

500

Step-by-step explanation:

If 1% is 2.5 then 100% is 250.  Since 250 is half of a number, you went then multiply by 2 to double that number which is 500.

5 0
3 years ago
Read 2 more answers
Help plssssssssssssssss
Alina [70]

Step-by-step explanation:

1. vertical angles. x = 5

2. supplementary x = 12

3. complementary x = 7

4 Supplementary x = 17

5. sQR = 118

RQT = 62

6 LNK = 47, JNM = 47

4 0
2 years ago
Read 2 more answers
Other questions:
  • Solve the equation below<br><br> 3h - 2( 4h - 5 ) = 10 - 5h
    14·2 answers
  • Which statement is true about the end behavior of the graphed function?
    6·2 answers
  • Which of the following best corresponds to the x-value where the function f(x)=cos x is a minimum in the interval x=|25,30|
    12·1 answer
  • What is the lower limit of f(x) = x^5 - 3x^3+ 24
    5·1 answer
  • What is the length of the hypotenuse of this triangle? Round to the nearest tenth.
    13·2 answers
  • I need help to solve this
    11·2 answers
  • m TMN = x + 72, m LMN = 166°, and m LMT = 96 + x. Find m LMT. what is the answer to this? ill make you the brainly
    6·1 answer
  • A weather balloon is 529 meters above the ground. Two weather stations, A and B, monitor the balloon’s progress. A weather ballo
    6·2 answers
  • 8×10^7×1.5×3^-1×10^-9​
    15·1 answer
  • I will give brainliest<br> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!