Stat Chapt 7 FA

$0.12 million

Major league baseball salaries averaged $3.26 million with a standard deviation of $1.2 million in a recent year. Suppose a sample of 100 major league players was taken. What was the standard error for the sample mean salary?

0001

For a population frame containing N = 1,007 individuals, what code number should you assign to the first person on the ist in order to use a table of random numbers?

Distribution is approximately normal with mean = 10 minutes and standard error = 0.8 minutes.

For air travelers, one of the biggest complaints is of the waiting time between when the airplane taxis away from the terminal until the flight takes off. This waiting time is known to have a right skewed distribution with a mean of 10 minutes and a standard deviation of 8 minutes. Suppose 100 flights have been randomly sampled. Describe the sampling distribution of the mean waiting time between when the airplane taxis away from the terminal until the flight takes off for these 100 flights.

if the shape of the population is symmetrical.

For sample size 16, the sampling distribution of the mean will be approximately normally distributed

regardiess of the shape of the population.

For sample sizes greater than 30, the sampling distribution of the mean will be approximately normally distributed

False

There can be only one sample selected from a population.

convenience sample

A company selling apparel online sends out emails every Monday to all its customers who made a purchase. This is an example of a

5

A population frame for a survey contains a listing of 72,345 names. Using a table of random numbers, how many digits will the code numbers for each member of your population contain?

Systematic sample

A telemarketer set the company's computerized dialing system to contact every 25th person listed in the local telephone directory. What sampling method was used?

False

As a population becomes large, it is usually better to obtain statistical information from the entire population.

statistic

At US Data Corporation's website, they advertised that "Because of our commitment to quality and our vast amount of industry knowledge and experience, we have grown to be one of Americ leading providers of mailing lists, marketing datą, sales leads and research data. We maintain datåbases of information on consumers and businesses nationwide that set industry standards for mission critical currency, reliability and accuracy." Trying to reach 500 potential donors for their annual phone donation campaign, a local fire department purchased list of donors from the company. This list is an example of a

0.050

At a computer manufacturing company, the actual size of computer chips is normally distributed with a mean of 1 centimeter and a standard deviation of 0.1 centimeter. A random sample of 12 computer chips is taken. What is the standard error for the sample mean?

True

If a simple random sample is chosen with replacement, each individual has the same chance of selection on every selection.

statistics

Sampling distributions describe the distribution of

False

Sampling error can be completely eliminated by taking larger sample sizes.

True

Sampling error can be reduced by taking larger sample sizes.

for a large n, it says the sampling distribution of the sample mean approximately normal, regardless of the shape of the population.

The Central Limit Theorem is important in statistics because

Stratified sample

The Dean of Students mailed a survey to a total of 400 students. The sample included 100 students randomly selected from each of the freshman, sophomore, junior, and senior classes on campus last term. What sampling method was used?

Simple random sample

The evening host of a dinner dance reached into a bowl, mixed all the tickets around, and selected the ticket to award the grand door prize. What sampling method was used?

A list of potential customers purchased from a database marketing company

The manager of the customer service division of a major consumer electronics company is interested in determining whether the customers who have purchased a DVD player made by the company over the past 12 months are satisfied with their products. Which of the following will be a good frame for drawing a sample?

0.200

The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed, with mean of 3.2 pounds and standard deviation of 0.8 pound. If a sample of 16 fish is taken, what would the standard error of the mean weight equal?

2.500

The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed, with mean of 3.2 pounds and standard deviation of 0.8 pound. If a sample of 25 fish yields a mean of 3.6 pounds, what is the Z-score for this observation?

67%

The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed, with mean of 3.2 pounds and standard deviation of 0.8 pound. What percentage of samples of 4 fish will have sample means between 3.0 and 4.0 poụnds?

False

The professor of a business statistics class wanted to find out the mean amount of time per week her students spent studying for the class. Among the 50 students in her class, 20% were freshmen, 50% were sophomores and 30% were juniors. She decided to select 2 students randomly from the freshmen, 5 randomly from the sophomores and 3 randomly from the juniors. This is an example of a systematic sample.

All of the above. - measures the variability of the mean from sample to sample - decreases as the sample size increases. - is never larger than the standard deviation of the population.

The standard error of the mean

convenience sample

To demonstrate a sampling method, the instructor in a class picked the first 5 students sitting in the last row of the class. This is an example of a

cluster sample

To find out the potential impact of a new zoning law on a neighborhood, the legislators conduct a focus group interview by inviting the members of the housing owner's association of that neighborhood. This is an example of a

judgment sample

To gather information on the preferences of instructors at universities on topics for a business statistics textbook that it will publish, a publishing company invited 10 faculty members who have adopted one of the textbooks that it has published. This is an example of a

D convenience sample

To obtain a sample of 10 books in the store, the manager walked to the first shelf next to the cash register to pick the first 10 books on that shelf. This is an example of a

True

Using different frames to generate data can lead to totally different conclusions.

A sample is usually not a good representation of the target population.

Which of the following is not a reason for selecting a sample?

It is always more informative by investigating a sample than the entire population.

Which of the following is not a reason for the need for sampling?

Stratified sample

Which of the following sampling methods is a probability sample?

Items or individuals are chosen without regard to their probability of occurrence

Which of the following scenarios will yield a nonprobability sample?

probability sample

Which of the following types of samples can you use if you want to make valid statistical inferences from a sample to a population?

All students in a class are divided into gróups according to the rows that they are seated. One of the groups is randomly selected.

Which of the following yields a cluster sample?

All students in a class are grouped according to their gender. A random sample of 8 is selected from the males and a separate random sample of 7 is drawn from the females.

Which of the following yields a stratified sample?

It allows us to disregard the shape of the population when n is large.

Why is the Central Limit Theorem so important to the study of sampling distributions?