An experiment was done to look at whether there is an effect of the number of hours spent practising a musical instrument and gender on the level of musical ability. A sample of 30 (15 men and 15 women) participants who had never learnt to play a musical instrument before were recruited. Participants were randomly allocated to one of three groups that varied in the number of hours they would spend practising every day for 1 year (0 hours, 1 hours, 2 hours). Men and women were divided equally across groups. All participants had a one-hour lesson each week over the course of the year, after which their level of musical skill was measured on a 10-point scale ranging from 0 (you can't play for toffee) to 10 ('Are you Mozart reincarnated?').
-An ANOVA was conducted on these data, and the results revealed significant main effects of gender and the number of hours spent practising. You predicted that some practice would be better than none, and that 2 hours would be better than 1. Which of SPSS's built-in contrasts should you use to test these hypotheses?
A)Repeated contrast
B)Helmert contrast
C)Simple contrast
D)Difference contrast

Question

An experiment was done to look at whether there is an effect of the number of hours spent practising a musical instrument and gender on the level of musical ability. A sample of 30 (15 men and 15 women) participants who had never learnt to play a musical instrument before were recruited. Participants were randomly allocated to one of three groups that varied in the number of hours they would spend practising every day for 1 year (0 hours, 1 hours, 2 hours). Men and women were divided equally across groups. All participants had a one-hour lesson each week over the course of the year, after which their level of musical skill was measured on a 10-point scale ranging from 0 (you can't play for toffee) to 10 ('Are you Mozart reincarnated?'). 
-An ANOVA was conducted on these data, and the results revealed significant main effects of gender and the number of hours spent practising. You predicted that some practice would be better than none, and that 2 hours would be better than 1. Which of SPSS's built-in contrasts should you use to test these hypotheses?
A)Repeated contrast
B)Helmert contrast
C)Simple contrast
D)Difference contrast

Quizplus · Accepted Answer

Helmert contrasts are suitable for comparing each level of an independent variable to the mean of the subsequent levels. This aligns with the hypothesis that some practice (1 or 2 hours) is better than none, and that more practice (2 hours) is better than less (1 hour).

An Experiment Was Done to Look at Whether There Is