Question

Above are the results of a drug trial. The scores are given for subjects in two different conditions – a placebo and an herbal supplement to improve memory. The scores represent a number of words correctly recalled after listening to a story. Please run the appropriate test in SPSS using a p-value or choosing the critical value from the t-table. If the results are statistically significant, calculate effect size by hand using Cohen’s d.

placebo	herbal supplement
12	13
14	13
14	15
11	15
12	11
13	14
12	12
10	11
12	13
14	13
12	13

Answer 1

Enter the both variable in SPSS of the following way

In SPSS, Click on Analyze -> Compare Mean -> Independent Sample T - Test .

Move 'Data' variable in Test variable(s) and 'Group' variable in Grouping variable, Click on Define Groups -> 1 as Group 1 and 2 as Group 2 and then click on OK , Ok button. The output be

Output:

Since P-value is 0.270 which is > alpha 0.05 so we accept H0

Thus we conclude that there is no significance difference between the means of two groups