Group Comparisons

Question 1

Ordinal

Answer 1

Ordered categories

Question 2

Nominal

Answer 2

Unordered categories

Question 3

Descriptive statistics

Answer 3

Determined by outcome variable

Question 4

Inferential statistics

Answer 4

Determined by both predictor and outcome variable

Question 5

Null Hypothesis

Answer 5

Prediction that there is no difference; cannot prove it, but we can fail to disprove it

Question 6

Research Hypothesis

Answer 6

The prediction we’re interested in testing; we require strong evidence to support the hypothesis and it must be mutually exclusive

Question 7

Student’s T

Answer 7

Quantifies the difference between the group means, taking into account both the variability and sample size; small t= no evidence that populations are different for outcome; large t= populations are likely to be different for outcome

Question 8

P value

Answer 8

A number between 0 and 1; the probability of finding the t from our samples if there is really no difference between populations; larger t-> smaller p value; large inferential stat=likely a real difference between samples; if p value is small, it’s very unlikely the diff. between samples is due to chance

Question 9

P > .05

Answer 9

Fail to reject Ho, not stat. significant, no evidence of a relationship

Question 9

Line Chart Main Effect and Interaction

Answer 9

Main effect: lines must be separated
Interaction: different patterns/slopes

Question 9

P < .05

Answer 9

Reject Ho, stat. significant, a real relationship

Question 9

Means comparison: Two predictor variables

Answer 9

If both are categorical, decide on story; if one is continuous/ordinal put on x axis [line graph]; if one is fixed quantity [like gender], put on x axis and data will be clustered by that variable