# Sampling, central limit theorem, normal distribution

Question 1

All of the following are reasons to sample except for:

a) Reduce sampling error

b) The research process is sometimes destructive.

c) Save time

d) For given resources, broaden the scope of the study.

Question 2

Sampling in which every unit of the population has the same probability of being selected into the sample is sometimes referred to as:

a) representative sampling

b) fair sampling

c) random sampling

d) nonrandom sampling

Question 3

The most elementary random sampling technique is:

a) simple random sampling

b) stratified random sampling

c) systematic random sampling

d) area random sampling

Question 4

In which of the following sampling techniques does the researcher number every item of the population before taking the sample?

a) systematic sampling

b) quota sampling

c) cluster sampling

d) simple random sampling

Question 5

The main reason for using stratified random sampling is to:

a) reduce costs

b) make certain that every kth item is selected

c) reduce sampling error

d) reduce non sampling error

Question 6

Fifty percent of a population possesses attribute X, thirty percent possesses attribute Y, and twenty percent possesses attribute Z. A researcher decides to include some people with attribute X, some with attribute Y, and some with attribute Z in her sample. Her sample consists of 80 people with attribute X, 70 people with attribute Y, and 50 people with attribute Z. The researcher has most likely done what type of sampling?

a) systematic sampling

b) simple random sampling

c) proportionate stratified sampling

d) disproportionate stratified sampling

Question 7

Another name for cluster sampling is:

a) stratified sampling

b) quota sampling

c) snowball sampling

d) area sampling

Question 8

Test markets are probably closest to which type of sampling?

a) cluster sampling

b) quota sampling

c) stratified sampling

d) snowball sampling

Question 9

In using judgment sampling, the researcher attempts to sample elements from the population by using her judgment. However, the researcher tends to make errors of judgment in one direction. These systematic errors are called:

a) consistencies

b) directional errors

c) biases

d) tendencies

Question 10

Which of the following sampling techniques is based on referral?

a) stratified

b) quota

c) area

d) snowball

Question 11

The central limit theorem states that which of the following is true:

Question 12

The central limit theorem states that for a given large sample size, if the shape of the population is unknown, the distribution of sample means is:

a) unknown

b) normal

c) platykurtic

d) skewed

Question 13

Suppose a population has a mean of 75 and a standard deviation of 14. If a researcher randomly samples 35 values from this population, the probability that >= 72 is:

a) 0.102

b) 0.5832

c) 0.398

d) 0.898

Question 14

Suppose a population has a mean of 84 and a standard deviation of 18. If a researcher randomly samples 37 values from this population, the probability that 80 <= <= 89 is:

a) 0.866

b) 0.043

c) 0.1331

d) 0.3669

Question 15

Suppose a population has a mean of 152 and a standard deviation of 22. If a researcher is randomly taking samples of size 42 from the population, 63% of the sample means are greater than what value?

a) 153.12

b) 151.56

c) 150.88

d) 154.64

Question 16

The Central Limit Theorem applies to sample proportions if sample size is large enough relative to the population proportion. How large of a sample size is needed?

a) n? p = .25

b) n? p> 5 and n? q> 5

c) n >= 30

d) n? p> 7 and n< 20

Question 17

Fifty-seven percent of the population has heard of brand x batteries. If 340 people are randomly selected from the population, what is the probability that the sample proportion who have heard of brand x batteries is greater than sixty percent?

a) 0.1314

b) 0.2755

c) 0.3686

d) 0.8686

Question 18

Suppose that 78% of all prerecorded music shoppers are under age 30. If a random sample of 250 prerecorded music shoppers is randomly taken, what is the probability that the sample proportion that is under age 30 is more than 76%?

a) 0.2764

b) 0.7764

c) 0.2236

d) 0.8131

Question 19

Suppose that 42% of all consumers who purchase bottled water from a supermarket prefer brand x. If a random sample of 425 such consumers is taken, what is the probability that between 35% and 38% prefer brand x?

a) 0.0457

b) 0.1056

c) 0.3944

d) 0.9507

Question 20

Suppose .27 of all workers would switch jobs if they had an opportunity. If 292 workers are randomly selected, what is the probability that between 82 and 90 would switch jobs if they had an opportunity?

a) 0.1628

b) 0.2651

c) 0.4279

d) 0.5907

https://brainmass.com/statistics/normal-distribution/sampling-central-limit-theorem-normal-distribution-101701

#### Solution Preview

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Question 1 Multiple Choice

All of the following are reasons to sample except for:

Reduce sampling error

The research process is sometimes destructive.

Save time

For given resources, broaden the scope of the study.

Answer: Reduce sampling error

Question 2 Multiple Choice

Sampling in which every unit of the population has the same probability of being selected into the sample is sometimes referred to as:

representative sampling

fair sampling

random sampling

nonrandom sampling

Answer: random sampling

Question 3 Multiple Choice

The most elementary random sampling technique is:

simple random sampling

stratified random sampling

systematic random sampling

area random sampling

Answer: simple random sampling

Question 4 Multiple Choice

In which of the following sampling techniques does the researcher number every item of the population before taking the sample?

systematic sampling

quota sampling

cluster sampling

simple random sampling

Answer: systematic sampling

Question 5 Multiple Choice

The main reason for using stratified random sampling is to:

reduce costs

make certain that every kth item is selected

reduce sampling error

reduce non sampling error

Answer: reduce costs

Question 6 Multiple Choice

Fifty percent of a population possesses attribute X, thirty percent possesses attribute Y, and twenty percent possesses attribute Z. A researcher decides to include some people with attribute X, some with attribute Y, and some with attribute Z in her sample. Her sample consists of 80 people with attribute X, 70 people with attribute Y, and 50 people with attribute Z. The researcher has most likely done what type of sampling?

systematic sampling

simple random sampling

proportionate stratified sampling

disproportionate stratified sampling

Answer: disproportionate stratified sampling

X= 80 40% 50%

Y= 70 35% 30%

Z= 50 25% 20%

200

Therefore, disproportionate stratified sampling

Question 7 Multiple Choice

Another name for cluster sampling is:

stratified sampling

quota sampling

snowball sampling

area ...

#### Solution Summary

Answers Multiple choice questions on sampling, central limit theorem, normal distribution