home *** CD-ROM | disk | FTP | other *** search
/ Apple Reference & Present…nuary (Partner) - Disc 2 / The Apple Reference and Presentations Library (Disc 2)(January 1994).iso / SAS Institute / US English / JMP Statistical / JMP-68K / JMP Demo Help / JMP Demo Help.rsrc / PICT_2290_Testing Variances Equal.png < prev    next >
Portable Network Graphic  |  1994-04-29  |  64KB  |  816x1056  |  8-bit (255 colors)
Labels: book | reckoner | sky
OCR: Tests that the Variances are Equal When the variances across groups are not equal, the usual analysis of variance assumptio are not satisfied and the Anova test is not valid. IMP gives four tests for equality group variances and an Anova that valid when the group sample variances are unequal Lhe behind the first three tests of equal variances IC perform an analysis of variance on response variable constructed fo measure the spread in each group The fourth test Bartlett's test which is similar to the likelihood ratio test under normal distributions click on test for more help 'Brien' c test Brown- Forsythe test Levine test Bartlett's test If the tests of equal variances reveal that the group variances are significantly different, th Welch Anova for the means should be used in place of the u ...