SCENARIO 18-8
Recently, a University Switched to a New Type

question 154

Short Answer

SCENARIO 18-8
Recently, a university switched to a new type of computer-based registration. The registrar is
concerned with the amount of time 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. $$\begin{array} { r l r l } \underline { \text { Day } } & \text { Range } & \underline { \text { Mean } } & \underline { \text { Std.Dev. } } \\1 & 10 & 5.250 & 3.4949 \\2 & 31 & 15.250 & 10.3060 \\3 & 13 & 20.375 & 4.9262 \\4 & 21 & 22.875 & 8.3911 \\5 & 35 & 8.500 & 11.3767 \\6 & 18 & 7.875 & 6.9372 \\7 & 25 & 11.250 & 8.5815 \\8 & 30 & 7.875 & 9.5235 \\9 & 17 & 10.250 & 6.3640 \\10 & 22 & 9.500 & 7.8740 \\11 & 27 & 7.875 & 8.7086 \\12 & 26 & 12.875 & 9.3723\end{array}$$
-Referring to Scenario 18-8, an R chart is to be constructed for the time required to register. One
way to create the lower control limit involves multiplying the mean of the sample ranges by $D _ { 3 }$ .
For this data set, the value of $D _ { 3 }$ is ________.

---

Definitions:

Materials Quantity Variance

The difference between the actual amount of materials used in production and the standard amount expected to be used, multiplied by the standard cost per unit.

Raw Materials Price

The cost of raw materials required in the manufacturing process, a critical factor in the overall production cost and pricing strategy.

Variance

The difference between a planned, budgeted, or standard amount and the actual amount incurred or realized.

Revenue Variance

The difference between actual revenue earned and expected revenue, often used in budgeting and financial analysis.