Chapter 10: Misconceptions
When people read, hear, or prepare research summaries,
they sometimes have misconceptions about what is or isn't "sound
practice" regarding the collection, analysis, and interpretation
of data. Here are some of these common (and dangerous) misconceptions
associated with the content of Chapter 10.
 In comparing the means of two groups, the null hypothesis
must be set up to say that one population mean is equal to the other
population mean.
 If the means of two groups are statistically compared
and found to be significantly different, those two means must be quite
different.
 A researcher who compares two means with an Ftest
is more sophisticated than the researcher who compares two means with
a ttest.
 Correlated ttests focuses on correlation coefficients.
 Twotailed ttests are used when 2 groups are compared
whereas onetailed tests are used in conjunction with onesample ttests.
 If two groups are compared with an analysis of variance,
the researcher's primary interest is in the comparative degree of variability
in each group.
 Two means that are significantly different at p <
.001 must be further apart than two means that are significantly different
at only p < .05.
 A test that has adequate power to detect large effects
has even greater power to detect small effects.
 When interested in comparing the means of two samples
that differ in size, smart researchers discard data from the larger
group in order to make the sample sizes equal which then causes the
t or Ftest to be robust.
