phstat clarification

Question 1

The personnel manager of a large insurance company would like to
evaluate the effectiveness of four different sales training programs.
Eight new recruits are assigned to each of the four training programs A
to D. The scores of the members in each group on an exam are recorded
below. In answering the questions below you must support your answers
with specific numerical output from the Excel analysis.

A B C D

66 72 61 63

74 51 60 61

82 59 57 76

75 62 60 84

73 74 81 58

97 64 55 65

87 78 70 69

78 63 71 80



Is there a significant difference between the four groups?

Which individual groups differ from each other?

What is the within groups variance and why is it part of the
calculations?

Question 2

An industrial psychologist wishes to study the effects of motivation on
sales in a particular firm. Of 24 new salespersons, 12 are paid an
hourly rate and 12 are paid a commission. The 24 individuals are
randomly assigned to two groups. The following data represent the sales
volume (in thousands of dollars) achieved during the first month on the
job.

Using a 0.05 level of significance is there evidence of a significant
difference in the two groups.

Explain what would happen to the findings if the variance of both groups
were much larger. Hint: Consult the formula for computing the t or z
value in a difference of means test. You could rerun the analysis and
compare outputs to answer this question.

Hourly Commission

256 224

212 261

239 254

216 228

222 273

236 234

207 285

219 225

228 237

225 232

241 277

230 245



Question 3

As you know from your marketing studies brand awareness is a key
consideration in promotion. An advertising manager wants to know whether
the campaign the company is currently running is achieving an average
awareness score of 80 or above. He distributes 50 questionnaires to
potential buyers. The questionnaire measures brand awareness on a 0-100
scale. The mean score is 82.3 with a standard deviation of 14.1.

Set up the null and alternative hypotheses.

Determine at the 0.05 level of significance whether the advertising
manager has achieved his brand awareness objective.

Rerun the analysis in part b but with a sample size of 150. If the
conclusion drawn from the analysis is different you must explain why.
Hint look at the formula for z or t in a test of a single mean and/or
compare your two outputs very carefully.