2 ~ Sampling and Measurement

Question 1

What is a variable?

Answer 1

A characteristic that can vary in value amoung subjects in a sample of population

Question 2

What is a measurement scale?

Answer 2

The values a variable can take

Question 3

When is a variable called quantitative?

Answer 3

When the measurement scale has numerical value

Question 4

When is a variable called categorical?

Answer 4

When the measurement scale is a set of categories

Question 5

Categorical values are also called…

Answer 5

Qualitative

Question 6

For a quantitative variable, the possible numerical values are said to form…

Answer 6

an interval scale

Question 7

What are the scales for categorical variable?

Answer 7

Nominal scale and ordinal scale

Question 8

What is a nominal scale?

Answer 8

The values are unordered, no high or low end

Question 9

What is an ordinal scale?

Answer 9

The values have a natural ordering of values

Question 10

When is a variable descrete?

Answer 10

If its possible values form a set of separate numbers

Question 11

When is a variable continuous?

Answer 11

If it can take an infinite continuum of possible real numbers

Question 12

Are categorical variables discrete or continuous?

Answer 12

Discrete

Question 13

Are quantitative variables discrete or continuous?

Answer 13

Both

Question 14

What is a sample size?

Answer 14

The number of subjects in a sample

Question 15

What is simple random sampling?

Answer 15

A method of sampling for which every possible sample of size n had equal chance of selection

Question 16

What is a simple random sample also called?

Answer 16

Random sample

Question 17

What is the most common method for selecting a random sample?

Answer 17

1) Number the subjects 2) generate a set of these numbers randomly 3) sample the subjects whose numbers were generated

Question 18

What is a sample survey?

Answer 18

A method of data collection where a sample of people are interviewed

Question 18

What is a sample survey?

Answer 18

A method of data collection where a sample of people are interviewed

Question 19

What is an observational study?

Answer 19

A study where the outcomes are observed without any experimental manipulation

Question 20

What is a sampling error?

Answer 20

the error that occurs when we use a statistics based on a sample to predict the value of a population parameter

Question 21

When does sampling bias occur?

Answer 21

From using nonprobability samples, such as the selection bias inherent in volunteer samples

Question 22

When does response bias occur?

Answer 22

When the subject gives an incorrect response, or the question wording or the way the interviewer asks the questions is confusing or misleading

Question 23

When does nonresponse bias occur?

Answer 23

When some samples subjects cannot be reached or refuse to participate or fail to answer some questions

Question 24

How does systematic random sampling work?

Answer 24

SRS selects a subject near the beginning of the sampling frame list, skips names and selects another subject, and so forth

Question 25

What is a stratified random sample?

Answer 25

A stratified random sample divides the population into separate groups called strata and then selects a simple random sample from each stratum

Question 26

When is a stratified random sampling called proportional?

Answer 26

When the sampled strata proportions are the same as those in the entire population

Question 27

What is cluster random sampling?