and dealing with nonnormal data, 151
and normal probability plot, 150
and SAS function PROBNORM, 181
(See data transformations)
Chi-square, 123
degrees of freedom, 166–167
one sample χ^2 test of independence, 123, 168
probability using SAS function PROBCHI, 249
r×2 sample χ^2 test, 123
sampling distribution, 93–94
statistic, 171
table of, 383
test assumptions, 167
two sample test of homogeneity, 124, 169
when to use, 94, 164
worked example, 170–172, 198
using SAS procedure PROC FREQ, 173
(See Figure 5.1, 130)
Choosing a statistical test, 118, 129
(See also Figure 5.1, 130)
Class intervals using PROC FORMAT in SAS, 63
Cochran’s Q test statistic, 199, 203
worked example, 202–203
Coefficient of determination (R-square in SAS output), 282
of variation in regression, 282
Combinatorial, 98
Confidence interval(s) CI, 6, 102
correlation, 291–292
difference in means, 305
difference in proportions 190–191
for mean predicted values, 280
for individual predicted value, 281
CI of correlation worked example, 291–292
CI of difference in means worked example, 305
CI of mean difference worked example, 310
CI of predicted individual response worked example, 271
CI of predicted mean response worked example, 270–271
Contingency table, 22
Continuous distribution, 104–106
Contrasts on means (See Planned comparisons of means)
Corrected sums of squares, 75, 265
Correlation, 9, 253–254
attenuation of, 210
partial, 294–295
Pearson’s 283–289
Point biserial, 210
significance of, 290–291
Spearman’s rank order, 210, 214
using SAS procedure PROC CORR, 292
and Fisher’s z transformation, 291–292
and normality assumption, 284
(See Confidence Interval, Pearson correlation)
Index 412