# Statistical Psychology

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A social psychologist was interested in how communication patterns can affect creative problem solving in small groups. seven groups of each of two types were formed: vertical and horizontal. In the vertical groups, participants were organized hierarchically, so that they could communicate and share information only with the persons above or below them. In the horizontal groups, there was no hierarchy; participants could communicate with all other group members. All groups worked on a series of complex problems, and number solutions produced by each group is recorded here. Did the groups differ in the number of solutions produced?

Vertical Group
13
12
11
11
9
8
8
Horizontal Group
13
15
12
15
18
10
14

• Statistical Psychology -

Find the mean first = sum of scores/number of scores

Subtract each of the scores from the mean and square each difference. Find the sum of these squares. Divide that by the number of scores to get variance.

Standard deviation = square root of variance

Z = (mean1 - mean2)/standard error (SE) of difference between means

SEdiff = √(SEmean1^2 + SEmean2^2)

SEm = SD/√(n-1)

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z score.