Business Statistics Chapter 8 Quiz

Sampling error is defined as _______. A (X bar - mu) B. σ C. σ/n D. N - n

A. (X bar - mu)

Mileage tests were conducted on a randomly selected sample of 100 newly developed automobile tires. the mean tread wear was 50,000 miles, with a standard deviation of 3,500 miles. What is the best estimate of the average tread life in miles for the entire population of these tires? A. 50,000 B. 3,500 C. 500 D. 35

A. 50,000

When all the items in a population have an equal chance of being selected for a sample, the process is called _____. A. simple random sampling B. z-score C. sampling error D. non-probability sampling

A. simple random sampling

All possible samples of size n are selected for a population and the mean of each sample is determined. What is the mean of the sample? A. the population mean B. it is larger than the population mean C. it is smaller than the population mean D. it cannot be estimated in advance

A. the population mean

It is often not feasible to study the entire population because it is impossible to observe all the items in the population A. true B. False

A. true

the true sampling error is usually not known because ______. A. µ is unknown B. µ is a random variable C. σ2 is unknown D. the sample mean canoe be computed

A. µ is unknown

A marketing firm is studying consumer preferences for winter fashions in four different months. From a population of women 18-21 years of age, a random sample of 100 women was selected in January. Another random sample of 100 women was selected in March. Another random sample of 100 women was selected in June. Another random sample of 100 women was selected in September. What is the sample size? A. 4 B. 100 C. 400 D. 1

B. 100

When doing research, knowing the population mean and other population parameters is essential A. True B. False

B. False

When testing the safety of cars using crash tests, a sample of one or two cars is used because ______. A. sampling is more accurate B. cars are destroyed C. it is quicker D. the population is very large

B. cars are destroyed

As the size of the sample increases, what happens to the shape of the distribution of sample means? A. it cannot be predicted in advance B. it approaches a normal distribution C. it is positively skewed D. it is negatively skewed

B. it approaches a normal distribution

What is the difference between a sample mean and the population mean called? A. standard error of the mean B. sampling error C. interval estimate D. point estimate

B. sampling error

Manufacturers were subdivided into groups by volume of sales. Those with more than $100 million in sales were classified as large; those from $50 to $100 million as medium size; and those between $25 and $50 million, and so on. Samples were then selected from each of these groups. What is this type of sampling called? A. simple random sampling B. stratified random sampling C. cluster sampling D. systematic sampling

B. stratified random sampling

For a distribution of sample means constructed by sampling 5 items from a population of 15, ______. A. the sample size is 15 B. there will be 3.003 possible sample means C. the mean of the sample means will be 3 D. the standard error will be 1

B. there will be 3,003 possible sample means

The mean of all sample means is ______. A. X bar B. µ C. σ D. α

B. µ

A statewide sample survey is to be made. First, the state is subdivided into counties. Seven counties are selected at random and further sampling is concentrated on these seven counties. What type of sampling is this? A. simple random B. systematic random sampling C. cluster sampling D. stratified sampling

C. cluster sampling

The size of the sampling error is _____. A. directly related to the sample size-- in other words, the larger the sample size, the larger the sampling error B. directly related to the population mean-- in other words, the larger the mean, the larger the sampling error C. inversely related to the sample size-- in other words, the larger the sample size, the smaller the sampling error D. inversely related to the population mean-- in other words, the smaller the standard deviation, the larger the sampling error

C. inversely related to the sample size00 in other words, the larger the sample size, the smaller the sampling error

To study the population of consumer perceptions of new technology, sampling of the population is preferred over surveying the population because_____. A. sampling is more accurate B. we can compute z-scores C. it is quicker D. sampling methods are simple

C. it is quicker

Sampling error is the difference between a sample statistic and its corresponding _____. A. sample mean B. variance C. population parameter D. trend

C. population parameter

When dividing a population into subgroups so that a random sample from each subgroup can be collected, what type of sampling is used? A. simple random sampling B. systematic sampling C. stratified random sampling D. cluster sampling

C. stratified random sampling

According to the central limit theorem _____. A the population mean and the mean of all sample means are equal B. increasing sample size decreases the dispersion of the sampling distribution C. the sampling distribution of the sample means is approximately normally rD. the sampling distribution of the sample means will be skewed

C. the sampling distribution of the sample means is approximately normally distributed

Which of the following is the standard error of the mean? A. σ B. x/n C. σ/ SqRt(n) D. s

C. σ/ SqRt(n)

For a given population, the mean of all sample means (X bar) of sample size n, and the mean of all (N) population observations (X) are ______. A. equal to (X bar) B. not equal C. equal to ( x bar - mu) D. equal to the population mean µ

D. equal to the population mean µ

Suppose we select every fifth invoice in a file. What type of sampling is this? A. random B. cluster C. stratified D. systematic

D. systematic