A set of sample scores from an experiment has an N = 28 and a mean = 52. H 1 is directional, predicting an effect of the independent variable which decreases the magnitude of the dependent variable. H 0 asserts the sample is a random sample from a population of scores where µ = 55 and s = 12. a = 0.05_{1 tail}. Using the z test to analyze the data, z obt = _________. A) - 1.322 B) - 0.250 C) - 7.000 D) - 0.132

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To use the z-test, we need to first calculate the standard error of the mean (SEM): SEM = s/√n = 12/√28 = 2.26. Then, we can calculate the z-score: z = (M - µ)/SEM = (52 - 55)/2.26 = -1.32. Since H1 is directional, we only consider one tail of the distribution (the left tail, in this case), and we find the critical z-value for α = 0.05 and a one-tailed test: z crit = -1.645. Since z obt = -1.32 > z crit = -1.645, we fail to reject H0.

A Set of Sample Scores from an Experiment Has an N