Question

A manufacturer of flash drives for data storage operates a production facility that runs on three 8-hour shifts per day. The following contingency table shows the number of flash drives that were defective and not defective from each shift. Shift Defective 7 a.m.-3 p.m 3 p.m.-11 p.m 11 p.m.-7 p.m Not Defective 113 90 76 18 4 The expected number of not defective flash drives manufactured between 3 p.m. and 11 p.m. is_ Multiple Choice O e90 $30 74.4 O 98.0

Answer 1

Here first we will find the complete table

Shift	Defective	Not Defective	Total
7am - 3pm	7	113	120
3 pm - 11 pm	10	90	100
11 pm - 7 am	4	76	80
Total	21	279	300

Here expected value for not defective flash drives in between 3pm to 11 pm = Total not defective flashdrive * Toal flashdrive in 3pm to 11 pm /Toal flashdrives in the survey

= 100 * 279/300 = 93.0

Option b is correct here.