Question

If the operations management department at Quality University wants to construct a p-chart for determining whether the four faculty teaching the basic P/OM course are in control with regard to the number of students who fail the course. Accordingly, he sampled 100 final grades from last year for each instructor, with the following results: What is the estimate of the mean proportion of failures for these instructors?

INSTRUCTOR NUMBER OF FAILURES
Prof. A 13
Prof. B 0
Prof. C 11
Prof. D 16
Select one:
A. .16
B. .40
C. .11
D. .13
E. .10

Answer 1

E. .10

Explanation:

Total number of grades sampled, n = 100

Proportion of failure = number of failure/ total number of grades sampled

Proportion of failure for Prof A = 13/100 = 0.13

Proportion of failure for Prof B = 0/100 = 0

Proportion of failure for Prof C = 11/100 = 0.11

Proportion of failure for Prof D = 16/100 = 0.16

The total proportion of failures of all instructors = 0.13+0+0.11+0.16 =0.14

Compute the estimate of the mean proportion of failures for the four instructors =0.4/4 =0.10

The estimate of the mean proportion of failures for these instructors is 0.10