Statistical Methods for Psychology

Section 2.8 Measures of Variability 37

Figure 2.12 Distribution of infant weight as a function of age

We suspect that composites of 32 faces would be more homogeneous, and thus would be

rated more similarly, than would composites of four faces.

The data are shown in Table 2.6.^9 From the table you can see that Langlois and

Roggman correctly predicted that Set 32 faces would be rated as more attractive than Set 4

(^9) These data are not the actual numbers that Langlois and Roggman collected, but they have been generated to have
exactly the same mean and standard deviation as the original data. Langlois and Roggman used six composite
photographs per set. I have used 20 photographs per set to make the data more applicable to my purposes in this
chapter. The conclusions that you would draw from these data, however, are exactly the same as the conclusions
you would draw from theirs.