Question

Will students wait longer for the arrival of an instructor who is a full professor than for one who is a graduate student? This question was investigated by counting how many minutes undergraduate students waited in two small seminar classes, one taught by a full professor and one taught by a graduate student. The data (in minutes) are as follows:

Graduate student instructor: 9, 11, 14, 14, 16, 19, 37

Full professor: 13, 15, 15, 16, 18, 23, 38, 31, 31

a. Use the pooled-variances t test to test the null hypothesis at the .05 level, two-tailed.

b. Find the limits of the 95% confidence interval for the difference of the two population means

PLEASE SHOW ALL WORK. How do you find the sample variance to calculate pooled variance?

Answer 1

a)

\

since test statistic does not falls in rejection region we fail to reject null hypothesis

we do not have have sufficient evidence to conclude that l students wait longer for the arrival of an instructor who is a full professor than for one who is a graduate student

b)

for 95 % CI & 14 df value of t=			2.145
margin of error E=t*std error =			9.892208
lower bound=mean difference-E=			-4.813
Upper bound=mean differnce +E=			14.972
from above 95% confidence interval for population mean =(-4.813,14.972)