Question 1

Major league baseball salaries averaged $3.26 million with a standard deviation of $1.2 million in 2009. Suppose a sample of 100 major league players was taken. What was the standard error for the sample mean salary?

Accepted Answer

A)  $0.012 million 
B)  $0.12 million 
C)  $12 million 
D)  $1,200.0 million

Question 2

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

Accepted Answer

A) True 
 B)False

Question 3

A sample of size 25 provides a sample variance of 400. The standard error, in this case equal to 4, is best described as the estimate of the standard deviation of means calculated from samples of size 25.

Accepted Answer

A) True 
 B)False

Question 4

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

Accepted Answer

A)  It allows us to disregard the size of the sample selected when the population is not normal. 
B)  It allows us to disregard the shape of the sampling distribution when the size of the population is large. 
C)  It allows us to disregard the size of the population we are sampling from. 
D)  It allows us to disregard the shape of the population when n is large.

Question 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?

Accepted Answer

A)  3 
B)  4 
C)  5 
D)  6

Question 6

A sampling distribution is a distribution for a statistic.

Accepted Answer

A) True 
 B)False

Question 7

Sampling distributions describe the distribution of

Accepted Answer

A)  parameters. 
B)  statistics. 
C)  both parameters and statistics. 
D)  neither parameters nor statistics.

Question 8

A manufacturer of power tools claims that the average amount of time required to assemble their top-of-the-line table saw is 80 minutes with a standard deviation of 40 minutes. Suppose a random sample of 64 purchasers of this table saw is taken. The standard deviation of the sampling distribution of the sample mean is ________ minutes.

Accepted Answer

The answer of A manufacturer of power tools claims that...

Question 9

The fact that the sample means are less variable than the population data can be observed from the standard error of the mean.

Accepted Answer

A) True 
 B)False

Question 10

TABLE 7-6
According to an article, 19% of the entire U.S. population have high-speed access to the Internet. Random samples of size 200 are selected from the U.S. population.
-Referring to Table 7-6, among all the random samples of size 200, 90% will have more than ________% who have high-speed access to the Internet.

Accepted Answer

The answer of TABLE 7-6
According to an article, 19% of...

Question 11

TABLE 7-1
Times spent studying by students in the week before final exams follow a normal distribution with standard deviation 8 hours. A random sample of 4 students was taken in order to estimate the mean study time for the population of all students.
-Referring to Table 7-1, what is the probability that the sample mean is more than 3 hours below the population mean?

Accepted Answer

The answer of TABLE 7-1
Times spent studying by students in...

Question 12

The Central Limit Theorem is important in statistics because

Accepted Answer

A)  for a large n, it says the population is approximately normal. 
B)  for any population, it says the sampling distribution of the sample mean is approximately normal, regardless of the sample size. 
C)  for a large n, it says the sampling distribution of the sample mean is approximately normal, regardless of the shape of the population. 
D)  for any sized sample, it says the sampling distribution of the sample mean is approximately normal.

Question 13

Items or individuals in a judgment sample are chosen with regard to their probability of occurrence.

Accepted Answer

A) True 
 B)False

Question 14

A manufacturer of power tools claims that the average amount of time required to assemble their top-of-the-line table saw is 80 minutes with a standard deviation of 40 minutes. Suppose a random sample of 64 purchasers of this table saw is taken. The probability that the sample mean will be less than 82 minutes is ________.

Accepted Answer

The answer of A manufacturer of power tools claims that...

Question 15

The amount of tea leaves in a can from a particular production line is normally distributed with μ = 110 grams and σ = 25 grams. A sample of 25 cans is to be selected. So, the middle 70% of all sample means will fall between what two values?

Accepted Answer

The answer of The amount of tea leaves in a...

Question 16

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

Accepted Answer

A) True 
 B)False

Question 17

TABLE 7-4
According to a survey, only 15% of customers who visited the web site of a major retail store made a purchase. Random samples of size 50 are selected.
-Referring to Table 7-4, what proportion of the samples will have less than 15% of customers who will make a purchase after visiting the web site?

Accepted Answer

The answer of TABLE 7-4
According to a survey, only 15%...

Question 18

A sample is always a good representation of the target population.

Accepted Answer

A) True 
 B)False

Question 19

As the sample size increases, the standard error of the mean increases.

Accepted Answer

A) True 
 B)False

Question 20

________ results from the exclusion of certain groups of subjects from a population frame.

Accepted Answer

The answer of ________ results from the exclusion of certain...

Exam 7: Sampling and Sampling Distributions

Major league baseball salaries averaged $3.26 million with a standard deviation of $1.2 million in 2009. Suppose a sample of 100 major league players was taken. What was the standard error for the sample mean salary?

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

A sample of size 25 provides a sample variance of 400. The standard error, in this case equal to 4, is best described as the estimate of the standard deviation of means calculated from samples of size 25.

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

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?

A sampling distribution is a distribution for a statistic.

Sampling distributions describe the distribution of

The fact that the sample means are less variable than the population data can be observed from the standard error of the mean.

The Central Limit Theorem is important in statistics because

Items or individuals in a judgment sample are chosen with regard to their probability of occurrence.

The amount of tea leaves in a can from a particular production line is normally distributed with μ = 110 grams and σ = 25 grams. A sample of 25 cans is to be selected. So, the middle 70% of all sample means will fall between what two values?

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

A sample is always a good representation of the target population.

As the sample size increases, the standard error of the mean increases.

________ results from the exclusion of certain groups of subjects from a population frame.