A researcher predicts that scores in treatment A will be higher than scores in treatment B.If the mean for the 10 participants in treatment A is 4 points higher than the mean for the 10 participants in treatment B and the data produce t = 2.095,what decision should be made? A)With $\alpha$ = .05,reject H₀ for either a one-tailed or a two-tailed test B)With $\alpha$= .05,fail to reject H₀ for either a one-tailed or a two-tailed test C)With $\alpha$= .05,reject H₀ for a one-tailed test but fail to reject for a two-tailed test D)With $\alpha$= .05,reject H₀ for a two-tailed test but fail to reject for a one-tailed test

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Since the researcher predicted that scores in treatment A will be higher than scores in treatment B, a one-tailed test is appropriate. The t-value of 2.095 is greater than the critical t-value of 1.833 (obtained from a t-table with 18 degrees of freedom at a significance level of 0.05 for a one-tailed test). Therefore, we reject the null hypothesis H₀ in favor of the alternative hypothesis that the mean score in treatment A is higher than the mean score in treatment B. However, we cannot reject the null hypothesis for a two-tailed test because the critical t-value would need to be higher than 2.100 (for a significance level of 0.025 with 18 degrees of freedom), which is not the case.

A Researcher Predicts That Scores in Treatment a Will Be α\alphaα

A Researcher Predicts That Scores in Treatment a Will Be $\alpha$