ABSTRACT
Statistical Guide: By comparing the standard deviations for two groups, we can determine which group is more variable. (See Exercise 12 for more information on the standard deviation.) Just as two means may differ solely because of random sampling errors, so can two standard deviations. Thus, when two standard deviations are being compared, the null hypothesis says that the observed difference between two standard deviations is due to sampling error. We can test for the significance of the difference between two standard deviations using the test described below.
Background Notes: Samples of 54 music teachers and 56 physical education teachers responded to these statements: (1) "Children with emotional and behavioral disorders will benefit from the interaction with typical children" and (2) "I like having children with orthopedic handicaps in my classroom" on a four-point scale from 1 (strongly agree) to 4 (strongly disagree). For statement 1, the means for the music and physical education teachers were 2.7 and 2.2, respectively. For statement 2, the means for the music and physical education teachers were 2.0 and 2.4, respectively. Thus, on the average, the music teachers were more negative on the first statement, and the physical education teachers were more negative on the second statement.
