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o a two-sample test for equality of means assuming unequal variances. Calculate

ID: 3052008 • Letter: O

Question

o a two-sample test for equality of means assuming unequal variances. Calculate the p-value using Excel. a-1) Comparison of GPA for randomly chosen college juniors and seniors: = 4.05, s1 = .20. n,-15, X2-435, s2 .30, n2 = 15, = .025, left-tailed test. (Negative values should be indicated by a minus sign. Round down your d.f. answer to the nearest whole number and other answers to 4 decimal places. Do not use "quick" rules for degrees of freedom.) d.f t-calculated p-value t-critical a-2) Based on the above data choose the correct decision. Reject the null hypothesis O Do not reject the null hypothesis b-1) Comparison of average commute miles for randomly chosen students at two community colleges: = 19, s1 = 5, n1-22, 2-25, s2-7, n2 = 19, = .05, two-tailed test. (Negative values should be indicated by a minus sign. Round down your d.f. answer to the nearest whole number and other answers to 4 decimal places. Do not use "quick" rules for degrees of freedom.) d.f t-calculated p-value t-critical (b-2) Based on the above data choose the correct decision.

Explanation / Answer

a-1) Degrees of freedom: 24.3918


Test Statistic, t: -3.2225
Critical t:        -2.062144
P-Value:           0.0018

a-2) Reject the null hypothesis

b-1)

Degrees of freedom: 32.0275

Test Statistic, t: -3.1128
Critical t:        ±2.036863
P-Value:           0.0039

b-2)
Reject the null hypothesis


c-1)
Degrees of freedom: 23.2829

Test Statistic, t: 0.9613
Critical t:        1.712997
P-Value:           0.1731
c-2)
Do do reject the null hypothesis