4: Sampling, Measurement and Hypothesis Testing

Question 1

Random sampling

Answer 1

each member of the population has an equal chance of being selected to be a member of the sample

Question 2

stratified sampling

Answer 2

Proportions of important subgroups in the population are represented precisely

Question 2

Probability sampling is and includes

Answer 2

Each member of the population has a definable probability of being selected for the sample

Random sampling
stratified sampling
cluster sampling

Question 3

Non probability sampling

Answer 3

selects samples based on the subjective judgment of the researcher rather than random selection

convenience sampling
purposive sampling
quota sampling
snowball sampling

Question 4

Cluster sampling

Answer 4

Researcher randomly selects a cluster of people all having the same feature in common
Helps for big populations

Question 5

Purposive sampling

Answer 5

A specific type of person is recruited for the sample

Question 6

Convenience sampling

Answer 6

A group of individuals who meet the general requirements for the study and are recruited in a variety of non-random ways
§ From the subject pool

Question 7

Quota sampling

Answer 7

The researcher attempts to accomplish the same goal as stratified sampling but does so in a non-random fashion

Question 8

Snowball sampling

Answer 8

Once a member of a particular group has been surveyed, the researcher asks that person to help recruit additional subjects through a network of friends

Question 9

Developing measures from constructs

Answer 9

Researchers define the constructs as precisely as possible - operational definitions

Question 10

how do we evaluate measures

Answer 10

with reliability and validity

Question 11

Content validity

Answer 11

Is the test fully representative of what it aims to measure

Question 12

Criterion validity

Answer 12

predictive validity: refers to whether a test can successfully predict some future behaviour.

Concurrent validity: meaningfully relates to some other measure of behaviour

Question 13

Interval Scale

Answer 13

Each unit increase in the scale is assumed to reflect the same change in the underlying measure.

Question 13

Construct validity

Answer 13

Accurately measures some construct - the operational definition

Convergent validity - yes to other scores related to the construct

Discriminant validity - not to scores unrelated to the construct

Question 13

Ordinal scale

Answer 13

Measurement scale in which the ordering of numbers is meaningful, but the metric (amount) is not.

rankings showing the relative standing of objects or individuals

Question 14

Ratio scales

Answer 14

The concepts of order and equal interval are carried over from ordinal and interval scales, but in addition the ratio scale has a zero point

Question 15

Descriptive statistics

Answer 15

summarize the data collected from the sample

mean, median (N+1)/2, and mode

variance: range, IQR (Q3-Q1)

standard deviation

Question 15

better to use median than mean when there are

Answer 15

outliers

Question 16

Variation is reported when the data represents ______ the standard deviation is reported when the data represents ______

Answer 16

the entire population of scores; a sample of scores from the population

Question 17

Type I Error

Answer 17

Rejecting the null hypothesis when it is true
chance of this happening are equal to alpha

Question 18

Type II Error

Answer 18

You fail to reject H0 but are wrong (there is a statistically significant difference)

Can occur when the measurements are not reliable or aren’t sensitive enough to detect true differences between groups, or you have a small sample size

Question 19

Alpha

Answer 19

want to be at least 95% confident that your results are NOT due to chance

Question 20

Effect size

Answer 20

reports the size of the differences between groups

Question 21

Power

Answer 21

One hopes to be able to reject H0
The chance of this happening is referred to as the power of the statistical test

Inverse relationship with Type II error