Statistical Methods Section 1.3

To determine customer opinion of their food quality, General Foods randomly selects 30 city blocks during a certain week and surveys all homes within the city blocks. Which type of sampling did the researchers use? Systematic sampling Convenience sampling Cluster sampling Random sampling Stratified sampling

Cluster

A statistics class with 36 students is arranged so that there are 6 rows with 6 students in each row, and the rows are numbered from 1 through 6. A die is rolled and a sample consists of all students in the row corresponding to the outcome of the die. This sample ______ a simple random sample. Is ____ a random sample.

Is not ; is

Research is conducted to determine if there is a relation between stomach cancer and alcohol consumption. Does the given description correspond to an observational study or an experiment? Observational study Experiment

Observational study.

A large company wants to administer a satisfaction survey to its current customers. Using their customer database, the company randomly selects 80 customers and asks them about their level of satisfaction with the company. Which type of sampling did the researchers use? Systematic sampling Convenience sampling Cluster sampling Random sampling Stratified sampling

Random

A man is selected by a marketing company to participate in a paid focus group. The company says that the man was selected because he was randomly chosen from all adults. Which type of sampling did the researchers use? Systematic sampling Convenience sampling Cluster sampling Random sampling Stratified sampling

Random sampling

In a poll conducted by a certain research center, 857 adults were called after their telephone numbers were randomly generated by a computer, and 79% were able to correctly identify the attorney general. Which type of sampling did the researchers use? Systematic sampling Convenience sampling Cluster sampling Random sampling Stratified sampling

Random sampling

To determine her stress level, Kery divides up her day into three parts: morning, afternoon, and evening. She then measures her stress level at 2 randomly selected times during each part of the day. Which type of sampling did the researchers use? Systematic sampling Convenience sampling Cluster sampling Random sampling Stratified sampling

Stratified

To estimate the percentage of defects in a recent manufacturing batch, a quality control manager at General Electic selects every 16th refrigerator that comes off the assembly line starting with the seventh until she obtains a sample of 50 refrigerators. Which type of sampling did the researchers use? Systematic sampling Convenience sampling Cluster sampling Random sampling Stratified sampling

Systematic

A researcher selects every 110th social security number and surveys the corresponding person. Which type of sampling did the researchers use? Systematic sampling Convenience sampling Cluster sampling Random sampling Stratified sampling

Systematic sampling

A researcher selects every 443th social security number and surveys the corresponding person. Which type of sampling did the researchers use? Systematic sampling Convenience sampling Cluster sampling Random sampling Stratified sampling

Systematic sampling

In a study of 425 women with a particular disease, the subjects completed a survey about their diet. Does the given description correspond to an observational study or an experiment? The given description corresponds to an observational study. The given description corresponds to an experiment. The given description does not provide enough information to answer this question.

The given description corresponds to an observational study.

In a survey, 1465 Internet users chose to respond to this question posted on a newspaper's electronic edition: " Is news online as satisfying as print and TV news?: 52% of the respondents said "yes." What is a major problem with the study? There is no blinding or replication, which has a high chance of leading to bias. The results apply only to Internet users. This is a convenience sample with voluntary response, which has a high chance of leading to bias. The sample is not very large.

This is a convenience sample with a high chance of leading to bias.

A market researcher has randomly selected four businesses in a certain region. She is surveying all the employees from each business. Which type of sampling did the researchers use? Systematic sampling Convenience sampling Cluster sampling Random sampling Stratified sampling

cluster sampling

A study involved 22,071 male physicians. Based on random selections, 11,037 of them were treated with aspirin and the other 11,034 were given placebos. The study was stopped early because it became clear that aspirin reduced the risk of myocardial infarction by a substantial amount. This is an _________ because the researchers _______________________ the individuals. What is a major problem with the study? There is no blinding or replication, which has a high chance of leading to bias. The results apply only to male physicians. This is a convenience sample with voluntary response, which has a high chance of leading to bias. The results apply only to individuals with heart disease.

experiment ; apply a treatment to The results apply only to male physicians.

For the same class described in part (a), the 36 student names are written on 36 individual index cards. The card are shuffled and six names are drawn from the top. This sample ______ a simple random sample. Is ____ a random sample.

is ; is

For the same class described in part (a), the six youngest students are selected.

is not ; is not

Systematic sample

is obtained by selecting every kth individual from the population (the first individual selected is a random number from 1 to k).

Cluster sample

is obtained by selecting individuals within a randomly selected group of individuals.

Stratified sample

is obtained by subdividing the population into at least two different subgroups (or strata) so that subjects within the same subgroup share the same characteristics and then a sample is drawn from each subgroup ( or stratum).

Random sample

is selected in such a way that each individual member of the population has the same chance of being selected.

A medical researcher tested for a difference in systolic blood pressure levels between male and female students who are 12 years of age. She randomly selected four males and four females for her study. This is an _________ because the researchers _______________________ the individuals. What is a major problem with the study? There is no blinding or replication, which has a high chance of leading to bias. The sample is too small. The sample includes male and female students. This is a convenience sample with voluntary response, which has a high chance of leading to bias.

observational study ; does not attempt to modify The sample is too small