Homework 1, Statistics 112, Fall 2004
This homework is due Thursday, September 16th at the beginning of class.
1. Moore and McCabe, 2.3.
2. Average salary paid to teachers and expenditures per pupil are two commonly used measures of the amount of money spent on education. Data for the average amount paid to teachers (in thousands) and spent per pupil (in thousands) in U.S. public schools in 1986 for the fifty states plus the District of Columbia are contained in the file schoolexpenditures.JMP under the Data Sets link on our web site.
(a)Using JMP, make a scatterplot with the average amount paid to teachers on the y-axis and the average amount spent per pupil on the x-axis. Print your scatterplot. Note: If you use Word, an easy way to do your assignment is to copy the JMP output into Word. Otherwise you may print your JMP output separately and hand in an assignment that refers clearly to the output.
(b)Label your home state in the scatterplot. See Lecture 1 for instructions on labeling points in JMP. Also label the state that is an outlier in both the y-direction and the x-direction. Does this state’s (the outlier state) relationship between average amount paid to teachers and average amount spent per pupil deviate from the general relationship between these two variables in the scatterplot?
3. Continuation of problem 2.
(a)Describe the direction and strength of the association between average amount paid per teacher and average amount spent per pupil.
(b)Will a state initiative to spend more on students by mandating smaller classroom sizes lead to more pay for teachers? Explain what the data suggests about this question.
4. Use the web to find two unrelated time series. By this, I mean two variables that are measured over time. For example, the two variables might be murders in the U.S. and cell phones in Asia. Make sure that you have at least ten years in which both variables are recorded. A large collection of time series is available at . Save your data file for future use.
(a)Enter the data into JMP and make a scatterplot of the two variables, where the year is the unit.
(b)Describe the association between the variables. What do you think explains the association (or lack thereof) between the two variables.