Exam 8: Sampling Methods and the Central Limit Theorem

Sampling error is defined as _________.

The size of the standard deviation of the sampling distribution of the mean relative to the standard deviation of the population under study is __________.

The American Auto Association reports the mean price per gallon of regular gasoline is $3.10, with a population standard deviation of $0.20. Assume a random sample of 16 gasoline stations is selected and their mean cost for regular gasoline is computed. What is the probability that the sample mean is between $2.98 and $3.12?

The Intelligence Quotient (IQ) test scores for adults are normally distributed with a mean of 100 and a standard deviation of 15. What is the probability we could select a sample of 50 adults and find the mean of this sample is less than 95?

Sampling from a population may be preferred because, contacting or listing the entire population would be too ___________ consuming.

Sampling error is the difference between a sample statistic and its corresponding _________.

According to the central limit theorem, ____________.

The tread life of tires mounted on light duty trucks follows the normal probability distribution with a mean of 60,000 miles and a standard deviation of 4,000 miles. Suppose you bought a set of four tires, what is the likelihood the mean tire life of these four tires is more than 66,000 miles?

Bones Brothers & Associates prepare individual tax returns. Over prior years, Bones Brothers has maintained careful records regarding the time to prepare a return. The mean time to prepare a return is 90 minutes and the standard deviation of this distribution is 14 minutes. Suppose 100 returns from this year are selected and analyzed regarding the preparation time. What is the standard error of the mean?

For a population that is not normally distributed, the distribution of the sample means will ________.

If the sampling distribution of the sample means approximates a normal distribution, then the population is normally distributed.

Sampling is required when crash testing cars because the products are __________.

The American Auto Association reports the mean price per gallon of regular gasoline is $3.10, with a population standard deviation of $0.20. Assume a random sample of 16 gasoline stations is selected and their mean cost for regular gasoline is computed. What is the likelihood the sample mean is greater than $3.08?

A population consists of 14 values. How many samples of size five are possible?

The Office of Student Services at a large western state university maintains information on the study habits of its full-time students. Their studies indicate that the mean amount of time undergraduate students study per week is 20 hours. The hours studied follows the normal distribution with a standard deviation of six hours. Suppose we select a random sample of 144 current students. What is the probability that the mean of this sample is between 19.25 hours and 21.0 hours?

The Intelligence Quotient (IQ) test scores for adults are normally distributed with a mean of 100 and a standard deviation of 15. What is the probability we could select a sample of 50 adults and find that the mean of this sample is between 98 and 103?

The Intelligence Quotient (IQ) test scores for adults are normally distributed with a mean of 100 and a standard deviation of 15. What is the probability we could select a sample of 50 adults and find that the mean of this sample exceeds 104?

The mean of all possible sample means is equal to ____________.

A __________________ assumes that each item or individual in the population has an equal chance of being included.

The standard error of the mean is directly related to the sample size.