Statistics

Question 1

What is the pearson correlation?

Answer 1

Extent to which the variability of a variable is related to another variable variability.

Question 2

What is the difference between one-tailed and two-tailed hypotheses?

Answer 2

One-tailed explains the direction (> or <) and two-tailed just asks whether there is a difference without specifying what difference.

Question 3

The determination coefficient (r squared) is

Answer 3

The shared variance in percentages

Question 4

What does regression estimates?

Answer 4

The extent to which other variables (independent, predictor) explain the variance of a variable (dependent, criterion/outcome).

Question 5

ax+b, which is the slope and which is the intercept?

Answer 5

a=slope
b=constant/intercept

Question 6

What are the conditions for a linear regression?

Answer 6

-Dependent variable continous, normal distribution
-Independent variable any level (normal distribution for cont.)
-Medium correlation between predictor and outcome (higher or equal to .30)
-Predictors must be orthogonal (correlation between them lower than .30)

Question 7

Research hypothesis is reject when p is lower or equal than alpha. True or false?

Answer 7

True

Question 8

What does the independent T-test do?

Answer 8

Compares the means of 2 independent samples.

Question 9

How are the variables in an independent T-test?

Answer 9

Independet variable=nominal level, dichotomous
Dependent variable=continuous (interval or ratio)

Question 10

Homogeneity of variances is a condition for T-test that can be checked using:

Answer 10

Levene test or Hartley’s F Max

Question 11

What are some types of dependent samples T-tests?

Answer 11

-Test-retest designs
-Natural pairs
-Analyse whether treatment affects investigated variable

Question 12

What does an ANOVA one-way do?

Answer 12

Compares the scores obtained on at least 3 independent samples (analysis of variance)

Question 13

ANOVA is an omnibus test. True or false?

Answer 13

True (it tests the overall effect without saying which group mean is higher or lower)

Question 14

What test can be applied if one of the three conditions for ANOVA are not met (dependent variable continuous, normal distribution on each sample, homogeneity of variance)?

Answer 14

Kruskal-Wallis Test

Question 15

What does post-hoc analysis do?

Answer 15

Computes the overall effect of independent variable on outcome (pairwise comparisons which control the error)

Question 16

What tests should be applied if variances are homogenous or if they are not?

Answer 16

Homogenous: Bonferroni test
Non-homogenous: Dunnett test