Chapter 7: Problem 22
A population has a normal distribution. A sample of size \(n\) is selected from this population. Describe the shape of the sampling distribution of the sample mean for each of the following cases. a. \(n=94\) b. \(n=11\)
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Chapter 7: Problem 22
A population has a normal distribution. A sample of size \(n\) is selected from this population. Describe the shape of the sampling distribution of the sample mean for each of the following cases. a. \(n=94\) b. \(n=11\)
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Consider a large population with \(\mu=60\) and \(\sigma=10\). Assuming \(n / N \leq .05\), find the mean and standard deviation of the sample mean, \(\bar{x}\), for a sample size of a. 18 b. 90
If all possible samples of the same (large) size are selected from a population, what percentage of all sample proportions will be within \(2.0\) standard deviations \(\left(\sigma_{\hat{p}}\right)\) of the population proportion?
The test scores for 300 students were entered into a computer, analyzed, and stored in a file. Unfortunately, someone accidentally erased a major portion of this file from the computer. The only information that is available is that \(30 \%\) of the scores were below 65 and \(15 \%\) of the scores were above 90 . Assuming the scores are approximately normally distributed, find their mean and standard deviation.
An investigation of all five major fires in a western desert during one of the recent summers found the following causes. \(\begin{array}{llll}\text { Arson } & \text { Accident } & \text { Accident } & \text { Arson } & \text { Accident }\end{array}\) a. What proportion of those fires were due to arson? b. How many total samples (without replacement) of size three can be selected from this population? c. List all the possible samples of size three that can be selected from this population and calculate the sample proportion \(\hat{p}\) of the fires due to arson for each sample. Prepare the table that gives the sampling distribution of \(\hat{p}\). d. For each sample listed in part c, calculate the sampling error.
In a January 2014 survey conducted by the Associated PressWe TV, \(68 \%\) of American adults said that owning a home is the most important thing or \(a\) very important but not the most important thing (opportunityagenda.org). Assume that this percentage is true for the current population of American adults. Let \(\hat{p}\) be the proportion in a random sample of 1000 American adults who hold the above opinion. Find the mean and standard deviation of the sampling distribution of \(\hat{p}\) and describe its shape.
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