Reference no: EM133624361

A school in New York City was built right next to an elevated subway track, so kids in one of the schools were exposed to the loud noise of subway trains approximately every four minutes. One side of the school building faced a nearby elevated subway; the other side faced away. Bronzaft matched second-, fourth-, and sixth-grade classrooms on the quiet side and on the noisy side, where a passing train would push the sound readings from 59 decibels to 89 decibels. Then she compared the average reading scores from the two sets of classrooms. She found that the children exposed to the transit noise were nearly a year behind in reading by the sixth grade, and the teacher had difficulty teaching.

Two caveats were made about the research. It's worth noting that Bronzaft's subway research, as with similar studies at airports and elsewhere, have some limitations. For one thing, Bronzaft couldn't randomly assign students to the noisy versus quieter classrooms. There were also relatively few classrooms to choose from, so there might have been some natural variation.

1.) In the quasi-experiment described here, what is the quasi-independent variable? What are its levels? What is the dependent variable?

2.) What type of quasi-experiment is it (choices below)? How can tell? Please relay your reasoning.

one-group posttest only

one-group pretest-posttest

one-group interrupted time-series with one group

posttest only nonequivalent groups

pretest-posttest nonequivalent groups

interrupted time-series design with nonequivalent groups

pretest-posttest design with switching replication

switching replication with treatment removal

3.) Which of the four big validities is the first caveat about? These were the validities described in the reading on experimental research/simple experiments.

4.) Which of the four big validities is the second caveat about? How big of a problem would this be for the study?