An instructor in an Operations Management course encourages

An instructor in an Operations Management course encourages students to come to every class through giving them extra credits for attendance. Therefore, each class the instructor passes around the attendance sheet for students to sign their names if they are in class. This is the summer session and therefore there is one class on every day. The instructor randomly picks up one week and wants to use a p chart to check whether the number of absent students is in control or not. This is a big class and there are 120 students enrolled in the online system. The number of students in class from Monday to Friday is below according to the attendance sheet. Use these data to determine the upper and lower control limits for the class attendance issue.

Solution

Part (a)

Average = total Absentee / Number of days = 45/5 = 9

Standard Deviation = Sqrt(Average) = sqrt(9) = 3 (sqrt = Square Root)

Upper Control Limit = (Average + 3 * Standard Deviation) = (9 + 3*3) = 18

Lower Control Limit = (Average - 3 * Standard Deviation) = (9 - 3*3) = 0

Part (b)

Yes the Attendance issue appers to be in control. This means that there donot appear to be absence that are outside of the lower and upper control limit. The absence of the student in the class appear within the limit.

Total number of student Enrolled	120
Days of week	No. of student present	No. of student absent
Monady	117	3
Tuesday	113	7
Wednesday	108	12
Thursday	113	7
Friday	104	16
Total		45