Question

decide if each of the following studies is an example of an observational study, an experimental study, or a statistical survey. 1. a researcher polls a sample of high school seniors to determine the numbers of hours of sleep they get during the week. he uses these answers to examine whether there is a correlation between lack of sleep and bad grades. 2. teachers in two second grade classrooms use different teaching methods to teach a mathematical concept to their students. they then compare the successes of their students on a common test. 3. a questionnaire concerning the quality of food in the cafeteria is distributed to students and staff in the cafeteria is distributed to students and staff in a high school. results of the survey members at a high school. results of the survey are used to make improvements in the cafeteria. 4. in order to study its customer service, a bank hires an observer to record the number of minutes that each customer waits in line at the local bank between the hours of noon and 1 pm. 5. a group of adult women with high cholesterol are divided into two groups in a research project concerning a new cholesterol medication. one group is given the new medication while the second group receives a placebo. after a month, the cholesterol levels of the two groups are reevaluated. 6. every 50th box of crackers on an assembly line is pulled from the line and weighed to determine if the true weight is consistent with what the package label states.

Explanation:

1.

A statistical survey involves collecting data from a sample (here, polling high school seniors) to analyze relationships (correlation between sleep and grades). No manipulation, just data collection via polling.

An experimental study has a treatment (different teaching methods) applied to groups (two classrooms) to compare outcomes (test success). Manipulation of teaching method (independent variable) to observe effect on test scores (dependent variable).

A statistical survey uses a questionnaire (distributed to students/staff) to gather data (quality of food) for improvement. Data collection from a sample (students/staff) via survey.

Answer:

Statistical Survey

2.