Top: the null distribution of the test statistic, with the p-value in orange and the rejection region (area α) hatched red. Bottom: the same null curve beside the true curve for the value you pick as the truth, with α, β and power. t-test power uses the noncentral t distribution and treats s as the true σ.
Sketch the null curve and shade the tail first, then compute. The worked solution builds line by line after a correct answer or when you ask for it.
Your jobEach case is a finished test, a confidence interval or an error story. Give the verdict as fast as you can: reject or fail to reject H₀, or name the error. Three right in a row doubles your points. Keys 1 and 2 pick an answer.
Press Start to begin.
Fictional settings and practice numbers chosen to look realistic. They are not clinical reference values or advice.
Wrong picks are fine here. Each one tells you why.