Determining Number of Observations

As a class project you have been asked to project the proportion of time a professor spends on various activities. You have decided to use the work sampling method. Your initial observations are shown.

Activity Observed / Number of Times Observed

Grading 4
Administrative paperwork 6
Preparing for class 5
Teaching class 5
Meeting with student(s) 8
On the phone 2
Working on research 6
Unavailable 4
Total 40

You are instructed that your estimates are to be within 5 percent of the true value with 97 percent confidence (z = 2.17).

Based on your initial observations, how many total observations are needed to estimate the proportion of time the professor spends on each activity?

Grading observations
Administrative paperwork observations
Preparing for class observations
Teaching class observations
Meeting with student(s) observations
On the phone observations
Working on research observations
Unavailable observations

After taking additional observations, the following data are available.

Activity Observed / Number of Times Observed

Grading 30
Administrative paperwork 50
Preparing for class 30
Teaching class 30
Meeting with student(s) 66
On the phone 17
Working on research 45
Unavailable 34
Total 302

Determine what proportion of time the professor spends teaching class.

% (Round your answer to 1 decimal place, the tolerance is +/-0.1. Omit a percent sign "%" in your answer.)

Determine what proportion of time the professor spends working on research.

% (Round your answer to 1 decimal place, the tolerance is +/-0.1. Omit a percent sign "%" in your answer.)

If the professor works approximately fifty-four hours per week instead of 302 hours, determine the amount of time that would normally be spent on each activity.

(Round your answers to 2 decimal places, the tolerance is +/-0.01.)

Grading hours
Administrative paperwork hours
Preparing for class hours
Teaching class hours
Meeting with student(s) hours
On the phone hours
Working on research hours
Unavailable hours