SCENARIO 15-8
Recently, a University Switched to a New Type

question 227

Short Answer

SCENARIO 15-8
Recently, a university switched to a new type of computer-based registration.The registrar is concerned with the amount of time (hours) students are spending on the computer registering under the new system.She decides to randomly select 8 students on each of the 12 days of the registration and determine the time each spends on the computer registering.The range, mean, and standard deviation of the times required to register are in the table that follows. $\begin{array}{cccc}\underline{\text { Day }} & \underline{\text { Range}}& \underline{\text { Mean }}& \underline{\text { Std.Dev. }}\\1 & 10 & 5.250 & 3.4949 \\2 & 31 & 15.250 & 10.3060 \\3 & 13 & 20.375 & 4.9262 \\4 & 21 & 22.875 & 8.3911 \\5 & 35 & 8.500 & 11.3767 \\6 & 18 & 7.875 & 6.9372 \\7 & 25 & 11.250 & 8.5815 \\8 & 30 & 7.875 & 9.5235 \\9 & 17 & 10.250 & 6.3640 \\10 & 22 & 9.500 & 7.8740 \\11 & 27 & 7.875 & 8.7086 \\12 & 26 & 12.875 & 9.3723\end{array}$

-Referring to SCENARIO 15-8, an R chart is to be constructed for the time required to register.One way to create the upper control limit involves multiplying the mean of the sample ranges byD4.For this data set, the value of D4 is .