An Instructor Gives a Test Before and After a Lesson

question 61

Essay

An instructor gives a test before and after a lesson and results from randomly selected students are given below.
At the 0.05 level of significance, test the claim that the lesson has no effect on the grade. Use the sign test. $\begin{array}{llllllllllllllll}\text { Before } & 54 & 61 & 56 & 41 & 38 & 57 & 42 & 71 & 88 & 42 & 36 & 23 & 22 & 46 & 51 \\\hline \text { After } & 82 & 87 & 84 & 76 & 79 & 87 & 42 & 97 & 99 & 74 & 85 & 96 & 69 & 84 & 79\end{array}$

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Definitions:

Variables

Elements or characteristics within a study or research that can change and potentially impact the study's results.

Negative Correlation

A relationship between two variables whereby they move in opposite directions.

Direct Correlation

A relationship between two variables where an increase in one variable is associated with an increase in the other, or a decrease in one is associated with a decrease in the other.

Negative Correlation

An interdependence between two variables marked by the rise of one and the decline of the other.