Chapter 8: Sampling, Sampling Methods, and the Central Limit Theorem

A marketing firm is polling 60 students at a college using a stratified sample. If two thirds of the students are women, and one quarter of the students are from out of state, how many out-of-state students should be polled?

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Choose the statement that best defines the Sampling Distribution of the Sample Mean.

A probability distribution of all possible sample means of a given sample size.

What is a simple random sample? Choose one.

A sample selected so that each member of the population has the same likelihood of being included.

Which one of the following statements is true about the dispersion of the distribution of sample means?

As the sample size increases, the variability in the sample means decreases.

Which of the following statements describe valid reasons to use a sample instead of evaluating a much larger population?

Contacting the whole population would be only marginally more accurate than a sample. Contacting the entire population would be time consuming.

Which of the following statements correctly describe the relationship between a population and a sample?

Samples are used to estimate population characteristics. A sample statistic is probably not exactly the same as the corresponding population characteristic A sample is a subset of the population.

Identify the steps required in taking a systematic random sample.

Select every kth member of the population from the starting point. Select a random starting point.

Which of the following is a simple random sample?

Ten cities in Illinois are randomly selected using a random number list.

Choose the statement that best describes sampling error.

The difference between a sample statistic and its corresponding population parameter.

Pick the statement that describes the formula for the standard error of the mean in ordinary language.

The standard error is equal to the population standard deviation divided by the square root of the sample size.

Which of the following is a systematic random sample random sample? Choose one.

To verify the accuracy of a automated beverage filling line, every 30th can is selected and weighed.

There are many reasons why it may be undesirable to sample an entire population. Which of the following is a reason that a modest size sample may be adequate?

Very few problems require 100% accuracy.

Which of the following is an expression that represents sampling error?

X𝑋-μ

Select the formula that would be used to find the z-value for a sample mean when we are applying the Central Limit Theorem.

z = x⎯⎯−μσ/n√

In cluster sampling the clusters are chosen from the population using simple random sampling. What kind of sampling is used within the individual clusters?

Random sampling

The shape of a sampling distribution tends to follow the normal probability distribution.

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Identify the steps that are followed in taking a stratified random sample.

Determine what portion of the sample should come from each strata. Measure the size of the strata as a proportion of the population. Take random samples from each strata.

Identify the steps involved in taking a cluster sample.

Divide the population into groups using naturally occurring boundaries. Select a random sample from each sub group. Randomly select a subset of clusters.

Choose the two statements that are correct descriptions of the sampling distribution of the sample mean.

It is a probability distribution of all possible sample means. It is a distribution of means from samples of all one size.