MKT 317 Lecture Notes - Variance, Confidence Interval, Interval Ratio
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= p : confidence intervals for both small (t) & large (z) sample 2 mean test. Z /2 both must be 30. Note: both same except use zcrit instead of tcrit & does not require the pooled variances: confidence interval for paired samples. Note: same except zcrit is used when nd 30 & tcrit is used when nd < 30: confidence interval for 2 proportions. Fcalc = larger sample variance/ smaller sample variance = s2. Reject h0 if fcalc > f /2, dfnum, dfdenom. Note: by always placing the larger sample variance in the numerator, we only have to examine the upper position of the distribution, i. e. the right tail. Degrees of freedom for fcritical dfnum = (n of sample in numerator) 1 dfdenom= (n of sample in denominator) 1. Notes: we always designate the population with the larger expected variance in the alternative as population #1. Reject: h0 if fcalc > f , dfnum, dfdenom.
