Chapter 7: Q.29 (page 429)
An unknown distribution has a mean of and a standard deviation of six. Let = one object from this distribution. What is the sample size if the standard deviation of is ?
Short Answer
The sample size is.
Chapter 7: Q.29 (page 429)
An unknown distribution has a mean of and a standard deviation of six. Let = one object from this distribution. What is the sample size if the standard deviation of is ?
The sample size is.
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Get started for freeCertain coins have an average weight of grams with a standard deviation of g. If a vending machine is designed to accept coins whose weights range from g to g, what is the expected number of rejected coins when randomly selected coins are inserted into the machine?
An unknown distribution has a mean of 25 and a standard deviation of six. Let X = one object from this distribution. What is the sample size if the standard deviation of ΣX is 42?
Determine which of the following are true and which are false. Then, in complete sentences, justify your answers.
a. When the sample size is large, the mean of is approximately equal to the mean of .
b. When the sample size is large, is approximately normally distributed.
c. When the sample size is large, the standard deviation of is approximately the same as the standard deviation of .
According to the Internal Revenue Service, the average length of time for an individual to complete (keep records for, learn, prepare, copy, assemble, and send) IRS Form is hours (without any attached schedules). The distribution is unknown. Let us assume that the standard deviation is two hours. Suppose we randomly sample taxpayers.
a. In words,
b. In words,
c.
d. Would you be surprised if the taxpayers finished their Form s in an average of more than hours? Explain why or why not in complete sentences.
e. Would you be surprised if one taxpayer finished his or her Form in more than hours? In a complete sentence, explain why.
Yoonie is a personnel manager in a large corporation. Each month she must review of the employees. From past experience, she has found that the reviews take her approximately four hours each to do with a population standard deviation of hours. Let Χ be the random variable representing the time it takes her to complete one review. Assume Χ is normally distributed. Let be the random variable representing the meantime to complete the reviews. Assume that the 16 reviews represent a random set of reviews.
Find the probability that the mean of a month’s reviews will take Yoonie from to hrs. Sketch the graph, labeling and scaling the horizontal axis. Shade the region corresponding to the probability.
a.
b. P(________________) = _______
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