Recently we conducted a small study with ten participants. Each participant completed the same two tests, 'Test A' and 'Test B', during one session. Five particpants (Group AB) performed test A first, while the remainder performed test B first (Group BA). The goals were:

1) To see if the two tests were equivalent

2) To establish whether the order of the tests had any effect on the relative scores on each test.

Goal 1

The combined data failed the Levenes test for homogeneity of variance (P = .028), and Test B data failed the Shapiro Wilk test for normaility (P = .008). A Wilcoxin Signed Ranks test revealed no significant difference between tests A & B (Z = -.634, P = .536)

Goal 2

Achieving goal two is a problem. We have used a One Way ANOVA to establish that group (i.e. AB or BA) was not a significant factor for either test (P =.496, and P =.436). However, while the data for both tests A and B passed Levene's tests, only group AB scores on test A passed a Shapiro Wilk test. We are unsure of which non parametric test to use as the Kruskal-Wallis ANOVA by ranks is only suitable for 3+ groups. It may be the case that we do not really know how to set this up properley in SPSS!

Any help would be much appreciated!