Deck 15: Are There Differences Between Groups or Conditions Mann-Whitney U and Wilcoxon Signed Rank Tests

Question 1

A Mann Whitney U test is the non-parametric equivalent of which type of parametric test?

A) One-way ANOVA
B) Pearson's correlation
C) Repeated t test
D) Independent t test

Answer 1

D
Explanation: See summary of parametric tests and their non-parametric equivalents on p216

Question 2

When conducting a Mann Whitney U, when ranking the data you should…

A) Rank all data at the same time, disregarding which condition they belong to
B) Rank the data from each condition separately
C) Only rank data where there are single examples of a particular value (e.g., only one score of 16)
D) Only rank data where there are multiple examples of a particular value (e.g., multiple scores of 16)

Answer 2

A

Question 3

When conducting a Mann Whitney U, a small calculated U value indicates…

A) A small sample size
B) A large sample size
C) A small difference between conditions
D) A large difference between conditions

Answer 3

D
Explanation: The smaller the summed rank score the more significant the difference between conditions

Question 4

When conducting a Mann Whitney U, the U₁ and U₂ values added together should be the same as…

A) n₁ + n₂
B) n₁ * n₂
C) n₁ / n₂
D) n₁ - n₂

Question 5

When conducting a Mann Whitney U, imagine you have run a study with 9 participants in one condition and 6 in the other. You have a two-tailed test and you wish to use an alpha level of .050. What would the critical value be?

A) 6
B) 6
C) 10
D) 12

Question 6

When conducting a Wilcoxon signed rank test, which values are ranked?

A) The scores in condition X
B) The scores in condition Y
C) The squared scores
D) The difference scores

Question 7

When conducting a Wilcoxon signed rank test, how is W+ calculated?

A) By squaring the positive signed ranks
B) By squaring the negative signed ranks
C) By summing the positive signed ranks
D) By summing the negative signed ranks

Question 8

When conducting a Wilcoxon signed rank test, how is N calculated?

A) Number of participants - 1
B) Number of participants - 2
C) Number of participants - the number of non- tied scores
D) Number of participants - the number of tied scores

Question 9

When conducting a Wilcoxon signed rank test, you have N=10, a two tailed test and an alpha level of .020. What is the critical value?

A) 8
B) 5
C) 3
D) 1

Question 10

In the Mann Whitney U birth order example, what is T²?

A) 48
B) 88
C) 52
D) 12

Question 11

In the Mann Whitney U birth order example, what is U₁?

A) 52
B) 12
C) 48
D) 88

Question 12

In the Wilcoxon signed rank text chocolate and mood example, what is W+?

A) -47.5
B) 7.5
C) 47.5
D) -7.5

Question 13

In the Wilcoxon signed rank text chocolate and mood example, what is W-?

A) -7.5
B) 47.5
C) 7.5
D) -47.5

Question 14

In the Wilcoxon signed rank text chocolate and mood example, what is N?

A) 12
B) 11
C) 10
D) 9