Question

want to test the hypothesis that students who study one week before score greater than students who study the night before, giving you the following hypotheses: Null Hypothesis: H1 = H2, Alternative Hypothesis: H1 > H2. A random sample of 31 students who indicated they studied early shows an average score of 86.19 (SD = 4.358) and 35 randomly selected procrastinators had an average score of 84.58 (SD = 6.631). Perform a two independent samples t-test assuming that early studiers are group 1 and procrastinators are group 2. What is the test statistic and p-value of this test? Assume the population standard deviations are the same. 1) Test Statistic: 1.10), P-value: 0.1274 2) Test Statistic: -1.149, P-Value: 0.1274 3) Test Statistic: 1.149, P-Value: 0.8726 4) Test Statistic: 1.149, P-Value: 0.2548 5) Test Statistic: -1.149, P-Value: 0.8726

Answer 1

Excel add-in (PH Stat) procedure: Step 1: In EXCEL, Select Add-InsPH Stat>Two-Sample Tests (Summarized Data). Step 2: Choose Pooled-Variance t Test. Step 3: In Data enteroUnder Hypothesized Difference. Step 4: Enter 0.05 Under Level of Significance. Step 5: In Population 1 Sample, enter Sample size as 31. Sample Mean as 86.19. and Sample Standard deviation as 4.358. Step 6: In Population 2 Sample, enter Sample size as 35. Sample Mean as 84.58, and Sample Standard deviation as 6.631. Step 7: Choose Upper-Tail Test under Test Options. Step 8: Click OK. Excel add-in (PH Stat) output:

Pooled-Variance t Test for the Difference Between Two Means (assumes equal population variances) Data Hypothesized Difference Level of Significance 0.05 Population 1 Sample Sample Size 31 Sample Mean 86.19 Sample Standard Deviation 4.358 Population 2 Sample Sample Size 35 Sample Mean 84.58 Sample Standard Deviation 6.631 30 34 Intermediate Calculations Population 1 Sample Degrees of Freedom Population 2 Sample Degrees of Freedom Total Degrees of Freedom Pooled Variance Standard Error Difference in Sample Means t Test Statistic 64 32.2617 1.4009 1.6100 1.1493 Upper-Tail Test Upper Critical Value p-Value Do not reject the null hypothesis 1.6690 0.1274

Correct Answer: 1). Test Statistic: 1.149, P-value: 0.1274.