Free Practice Quiz Question List

06 Sampling and Sampling Distributions Online Quiz Questions

Use this free practice quiz with 20 questions to review 06 Sampling and Sampling Distributions, test your knowledge, and prepare for your next test or exam.

20 questions

True or false

1 point

True or false: Increasing the size of a voluntary-response sample automatically eliminates selection bias.

A
True
B
False

Choose one

1 point

A university wants every class year represented in a sample. Which plan uses stratified sampling?

A
Randomly select 100 students from the complete university enrollment list.
B
Randomly select several residence halls and survey all students living in them.
C
Divide students by class year and randomly select students from each year.
D
Select students who happen to be studying in the library.

Fill in the blank

1 point

The of a statistic is the probability distribution of that statistic over all possible random samples of a specified size from a population.

Written response

1 point

A population has standard deviation $\sigma=12$ , and a random sample has size $n=36$ . What is the standard error of the sample mean?

Choose all

1 point

Which conditions support using the Central Limit Theorem to approximate the sampling distribution of a sample mean? Select all that apply.

A
The sample is obtained through a probability-based method.
B
The observations are independent, or dependence is negligible.
C
The population must be exactly Uniform.
D
The sample size is adequate for the population shape and possible skewness.
E
The sample must contain exactly 30 observations.

True or false

1 point

True or false: If the usual random-sampling and independence conditions hold, the sample mean is centered at the population mean over repeated samples.

A
True
B
False

Choose one

1 point

A customer list contains $N=10{,}000$ customers, and a systematic sample of $n=100$ customers is desired. What sampling interval is appropriate?

A
10
B
50
C
99
D
100

Fill in the blank

1 point

For the sampling distribution of a sample proportion to be approximately Normal, a common check is $np\ge$ and $n(1-p)\ge$ .

Written response

1 point

What is the name of the adjustment that may be applied to a standard error when sampling without replacement from a finite population and the sample is a substantial fraction of that population?

Choose all

1 point

Which sampling methods are especially vulnerable to selection bias because participation is linked to access or willingness to respond? Select all that apply.

A
A convenience sample of customers who enter a store during one afternoon.
B
A simple random sample drawn from a complete customer list.
C
A voluntary-response online poll about satisfaction.
D
A stratified sample that randomly selects customers from each region.

Open ended

1 point

Explain the difference among a population distribution, a sample distribution, and a sampling distribution. Include what is being distributed in each case and how repeated sampling enters the definition.

Choose one

1 point

A sampling distribution of $\bar{X}$ has mean 80 and standard error 2. What is the standardized value of an observed sample mean of 84?

A
$0.5$
B
$1$
C
$2$
D
$4$

Choose one

1 point

A university wants each class year to be represented in a sample. It divides students into first-year, sophomore, junior, and senior groups, then randomly selects students from each group. Which sampling method is being used?

A
Randomly select several residence halls and survey every student living in the selected halls.
B
Divide students by class year, then randomly select students from each class year.
C
Ask students who happen to be in the library to complete a questionnaire.
D
Select every 50th student from an alphabetized list after choosing a random starting point.

Choose one

1 point

Which option describes systematic sampling from an ordered list of customers?

A
Select 100 customers entirely at random from the list.
B
Divide customers into regions and randomly sample from every region.
C
Select every 100th customer from an ordered list after choosing a random starting position among the first 100 positions.
D
Randomly select several customer neighborhoods and survey all customers in those neighborhoods.

Choose one

1 point

Which description best defines the sampling distribution of a statistic?

A
The distribution of all individual values in the population.
B
The distribution of individual observations in one particular sample.
C
The distribution of population parameters calculated from one sample.
D
The distribution of a statistic calculated from all possible random samples of a specified size.

True or false

1 point

True or false: If the sample size is at least 30, the Central Limit Theorem guarantees that the sample mean has an approximately Normal sampling distribution, regardless of the population distribution or sampling method.

A
True
B
False

Written response

1 point

A population has standard deviation $\sigma=12$ , and a random sample has size $n=36$ . What is the standard error of the sample mean? Enter the value as a number in the same measurement units as the observations.

Choose one

1 point

According to the square-root relationship for the standard error of a sample mean, what change in sample size is needed to reduce the standard error to one-half its current value?

A
Multiply the sample size by 4.
B
Multiply the sample size by 2.
C
Divide the sample size by 2.
D
Increase the sample size by 1.

Written response

1 point

What is the statistical term for a numerical summary calculated from a sample?

Choose one

1 point

Which statement correctly describes the effect of increasing the sample size on a biased sampling method?

A
A very large sample always eliminates bias because random error becomes small.
B
A large sample guarantees that the sampling frame represents the target population.
C
A very large sample can still give a precise estimate of the wrong quantity when the sampling method is biased.
D
Increasing sample size has no effect on the variability of a sample statistic.