Question

A researcher wants to determine the effect of an energy drink on people's productivity. 12 people volunteered to participate in the study. The participants were given two equally difficult tasks, one before having the energy drink and one after having the energy drink. The time that each person took to complete each task was recorded. The researcher wants to know whether task completion time after consuming the energy drink is less than that before consuming it. The results of the study are shown below.

Answer 1

The critical t-value for testing at the 0.1 level of significance?

Run a t-Test: Paired Two Sample for Means analysis in excel followed by below procedures:

1. Go to data tab --> data analysis --> choose t-Test: Paired Two Sample for Means

с t-Test: Paired Two Sample for Means ? Х Input OK Variable 1 Range: $A$1:$A$13 1 Cancel Variable 2 Range: $B$1:$B$13 1 Help Hypothesized Mean Difference: 0 B 1 Before After 2 23 3 31 4 44 5 28 6 24 7 39 8 19 9 28 10 35 11 41 12 31 13 37 14 Labels 19 29 36 29 20 34 16 25 33 37 28 30 Alpha: 0.1 Output options $F$4 1 O Qutput Range: O New Worksheet Ply: New Workbook

Result:

1 Before 2 3 4 5 6 7 t-Test: Paired Two Sample for Means After 23 31 44 28 24 39 19 28 35 41 31 37 19 29 36 29 20 34 16 25 33 37 28 30 After 28.00 46.36 12.00 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Mean Variance Observations Pearson Correlation Hypothesized Mean Difference df t Stat P(T<=t) one-tail t Critical one-tail P(T<=t) two-tail t Critical two-tail Before 31.67 59.52 12.00 0.96 0.00 11.00 5.41 0.00 1.36 0.00 1.80