The Effects of Educational Television
Is educational television an effective teaching aid? “The Electric Company” was a television programme that ran on US TV from 1971 to 1977. The programme used sketch comedy to provide an entertaining way of helping elementary school children develop their grammar and reading skills. It was widely credited by many teachers in US schools as having important effects on the literacy skills of second-, third-, and fourth-grade children. In this section, you will analyse data from an experiment that involved randomly assigning classes of children to watch “The Electric Company”. You will investigate what reading gains, if any, were made classes as part of this experiment.
The unit of analysis in this data is a class of children, and there are 192 classes in the data. Each class was
either treated (to watch the program) or control (to not watch the program). The outcome of interest is the
average score on a reading test administered at the end of each year called post.score. In addition to the
treatment and outcome, the data also contains information on the year grade of the class and the score on
the same reading test as adminstered before the treatment took place:
Question 2 (10 marks)
a. Make a scatter plot which compares student scores at the beginning of the year to student scores at the end of the year.
b. Make a box plot which depicts student scores at the end of the year as a function of the grade they are in.
c. Estimate three linear regression models. The first should predict post.score with only the treatment variable. The second regression model should be the same as the first, but should also control for student grade. The third model should be the same as the second, but should also control for pre.score.
d. Summarise these models in terms of how much of the variation in post.score they “explain”. What does
this tell us about the relationships between 1) the grade a student is in and reading ability, and 2) students’
prior performance on the test and current performance on the test?