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

question 39

Essay

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, construct an $\bar { X }$ chart for the time required to register.

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Definitions:

Negative Correlation

A statistical relationship between two variables where one variable increases as the other decreases.

Confounding Variables

Factors other than the independent variable that might cause changes in the dependent variable, potentially misleading the results of a study.

Original Variables

Fundamental or initial factors or conditions that can influence outcomes in scientific research or statistical analysis.

Reverse-scored Items

Questions in a survey or test designed in such a way that high values indicate the opposite of what is being measured, used to control for response bias.