Statistical analysis

Question 1

what are inferential statistics used for

Answer 1

a decision tool for rejecting null hypothesis

Question 2

what are the characteristics of parametric tests

Answer 2

1. more powerful
2. make assumptions about data
   - data is interval
   - data is normally distributed
   - homogeneity of variance
3. non parametric equivalent tests

Question 3

what are t tests used for

Answer 3

comparing 2 means

Question 4

why should t tests not be repeated over and over

Answer 4

increases the likelihood of a type 1 error

Question 5

what could be used if there are more than 2 means

Answer 5

ANOVA test:

• compares 3 or more mean scores
• an IV with 3 or more levels
• more than 2 IVs
• data must satisfy parametric assumptions

Question 6

what can an ANOVA test tell us

Answer 6

Null hypothesis (no difference between means), experimental (there is a difference), cannot tell where the difference is (Post-hoc tests and planned comparisons)

Question 7

what is the F ratio

Answer 7

F= between groups variance/within groups variance

• between groups= variation of group means about overall mean (explained effect)
• within groups= average variation across groups (unexplained error)
• resultant statistic is the F ratio

Question 8

give examples of post hoc tests

Answer 8

1. bonferroni and Tukey- assumptions met
2. Hochbergs GT2 and Gabriels- different sample sizes
3. Dunnets T3 and C- different sample variances