STAT 301 - Business Statistics
Lecture Review #22 - Analyzing Independent Means

A handout describing procedures useful in analyzing data from independent samples was distributed in class. If you did not get a copy (or if you mislaid yours), the handout is also available here.

Review questions:

1) What distinguishes independent samples from paired data?

2) What is the basic concept underlying the analysis of data from two independent samples?

3) What is a pooled variance? When is it used?

Computational exercises:

1) Mortimer Snodgrass wishes to determine whether basketweaving or sleep technology majors get higher starting salaries upon graduation. He gets salary data on eleven recent graduates. Their salaries, in thousands of dollars, are given below:

Perform an appropriate hypothesis test to investigate Mortimer's research question.

2) One hundred randomly selected students were asked to rate the qualifications of two job candidates based on a resume. Half were given the resume for a mythical John Benson and half were given another resume, identical to the first in all respects except for the name Mary Benson. Results are summarized below.

Is the difference in the average rating statistically significant?

SOLUTIONS:
1) pooled variance = 9.44, t = 2.89
2) pooled variance = 3.037, t = 0.60