# Question: This problem concerns course scores on a 0 100 scale for

This problem concerns course scores (on a 0–100 scale) for a large undergraduate computer programming course. The class is composed of both underclassmen (freshmen and sophomores) and upperclassmen (juniors and seniors). Also, the students can be categorized according to their previous mathematical background from previous courses as “low” or “high” mathematical background. The data for these students are in the file P09_75.xlsx. The variables are:

• Score: score on a 0–100 scale

• Upper Class: 1 for an upperclassman, 0 otherwise

• High Math: 1 for a high mathematical background, 0 otherwise

For the following questions, assume that the students in this course represent a random sample from all college students who might take the course. This latter group is the population.

a. Find a 90% confidence interval for the population mean score for the course. Do the same for the mean of all upperclassmen. Do the same for the mean of all upperclassmen with a high mathematical background.

b. The professor believes he has enough evidence to “prove” the research hypothesis that upperclassmen score at least five points better, on average, than lowerclassmen. Do you agree? Answer by running the appropriate test.

c. If a “good” grade is one that is at least 80, is there enough evidence to reject the null hypothesis that the fraction of good grades is the same for students with low math backgrounds as those with high math backgrounds? Which do you think is more appropriate, a one-tailed or two-tailed test? Explain your reasoning.

• Score: score on a 0–100 scale

• Upper Class: 1 for an upperclassman, 0 otherwise

• High Math: 1 for a high mathematical background, 0 otherwise

For the following questions, assume that the students in this course represent a random sample from all college students who might take the course. This latter group is the population.

a. Find a 90% confidence interval for the population mean score for the course. Do the same for the mean of all upperclassmen. Do the same for the mean of all upperclassmen with a high mathematical background.

b. The professor believes he has enough evidence to “prove” the research hypothesis that upperclassmen score at least five points better, on average, than lowerclassmen. Do you agree? Answer by running the appropriate test.

c. If a “good” grade is one that is at least 80, is there enough evidence to reject the null hypothesis that the fraction of good grades is the same for students with low math backgrounds as those with high math backgrounds? Which do you think is more appropriate, a one-tailed or two-tailed test? Explain your reasoning.

## Answer to relevant Questions

A cereal company wants to see which of two promotional strategies, supplying coupons in a local newspaper or including coupons in the cereal package itself, is more effective. The company randomly chooses 80 Kroger’s ...Explore the relationship between the selling prices (Y) and the appraised values (X) of the 148 homes in the file P02_11.xlsx by estimating a simple linear regression model. Interpret the standard error of estimate se and R2 ...The file P10_08.xlsx contains data on the top 200 professional golfers in 2009. a. Create a new variable, Earnings per Round, and the ratio of Earnings to Rounds. Then create five scatter plots and corresponding ...A trucking company wants to predict the yearly maintenance expense (Y) for a truck using the number of miles driven during the year (X1) and the age of the truck (X2, in years) at the beginning of the year. The company has ...Using the sample data given in the file P10_10.xlsx, use multiple regressions to predict the selling price of houses in a given community. Proceed as follows.a. Add one explanatory variable at a time and estimate each ...Post your question