In Chapter 13, Exercise 11 related midterm and final exam scores for a sample of students:

\[\text { Midterm }(X): \text { Range }=0-100, \bar{X}_{i}=68.67, s_{X}=12.44 ; \text { Final exam }(Y): \text { Range }=0-100, \bar{Y}=77.50, s_{Y}=9.38 \text {, }\]

Correlation: \(r=.85\)

a. Calculate the regression equation predicting final exam scores from midterm scores and draw it in into a scatterplot.

b. What final exam score would you predict for a student with a midterm exam score of 75?

Chapter 13, Exercise 11

What makes a person a "leader"? A social psychologist hypothesizes that the extent to which people are perceived to be leaders is positively related to the amount of talking they do, regardless of what they are actually saying. She conducts an experiment in which groups of participants solve a problem together. One of the participants in each group is a confederate who speaks a different number of sentences for different groups, half of which are designed to help the group solve the problem and half of which are not helpful. Following the group work, the confederate is rated by the other participants on his leadership ability (1=$(1=$ low, 10=$10=$ high )$)$. The following data represent the findings of this fictional researcher.

Transcribed Image Text:

Group # Sentences Spoken Rating of Leadership 1 4 5 2 10 6 3 29 7 4 22 9 5 6 2 6 7 3 7 18 8 8 15 4