Yule et al XXXXXXXXXXcollected the scores on each of ten cognitive tests from the Wechsler series on 150 children. By means of their scores on a test of reading ability, the children were divided into...

Yule et al. (1969) collected the scores on each of ten cognitive tests from the Wechsler series on 150 children. By means of their scores on a test of reading ability, the children were divided into “good” readers and “poor” readers. The covariance matrices of the two groups are shown in Table 16.4.

1. Calculate the correlation matrix for each group. 2. Prior information suggests that the first five tests are “verbal” and the last five “performance” tests. Fit a correlated two-factor model to the correlation matrix of both the “good” readers and the “poor” readers. Construct the relevant path diagrams and assess the goodness of fit of the model in each group. 3. Does the two-factor model fit in both or either groups?

4. How would you proceed to test that the two-factor model is identical in each group? Does such a model fit the data? 5. Summarize what you have found out about the covariance structure in the two groups of readers.