The shape of the distribution of the time required to get an oil change at a 20-minute oil-change facility is skewed right. However, records indicate that the mean time is 21.3 minutes, and the standard deviation is 3.1 minutes. Complete parts (a) through (c) below. Click here to view the standard normal distribution table (page 1). Click here to view the standard normal distribution table (page 2). (a) To compute probabilities regarding the sample mean using the normal model, what size sample would be required? Choose the required sample size below. A. The normal model cannot be used if the shape of the distribution is skewed right. B. The sample size needs to be less than 30. C. Any sample size could be used. D. The sample size needs to be greater than 30. (b) What is the probability that a random sample of n = 35 oil changes results in a sample mean time less than 20 minutes? The probability is approximately . (Round to four decimal places as needed.)

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
18th Edition
ISBN:9780079039897
Author:Carter
Publisher:Carter
Chapter10: Statistics
Section10.4: Distributions Of Data
Problem 19PFA
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The shape of the distribution of the time required to get an oil change at a 20-minute oil-change facility is skewed right.
However, records indicate that the mean time is 21.3 minutes, and the standard deviation is 3.1 minutes. Complete parts
(a) through (c) below.
Click here to view the standard normal distribution table (page 1).
Click here to view the standard normal distribution table (page 2).
(a) To compute probabilities regarding the sample mean using the normal model, what size sample would be required?
Choose the required sample size below.
A. The normal model cannot be used if the shape of the distribution is skewed right.
B. The sample size needs to be less than 30.
C. Any sample size could be used.
D. The sample size needs to be greater than 30.
(b) What is the probability that a random sample of n = 35 oil changes results in a sample mean time less than 20
minutes?
The probability is approximately
(Round to four decimal places as needed.)
Transcribed Image Text:The shape of the distribution of the time required to get an oil change at a 20-minute oil-change facility is skewed right. However, records indicate that the mean time is 21.3 minutes, and the standard deviation is 3.1 minutes. Complete parts (a) through (c) below. Click here to view the standard normal distribution table (page 1). Click here to view the standard normal distribution table (page 2). (a) To compute probabilities regarding the sample mean using the normal model, what size sample would be required? Choose the required sample size below. A. The normal model cannot be used if the shape of the distribution is skewed right. B. The sample size needs to be less than 30. C. Any sample size could be used. D. The sample size needs to be greater than 30. (b) What is the probability that a random sample of n = 35 oil changes results in a sample mean time less than 20 minutes? The probability is approximately (Round to four decimal places as needed.)
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