In this scenario, what is/are the independent variable[S]
Student Name:______________________________
1. Read the following survey item and identify/explain what might be wrong with it: “Should residents of the city spend more money on parks and road improvements?”
2. Read the following survey item and identify/explain what might be wrong with it:
“Do you think it is important to reduce the huge amount of money spent during campaigns?”
3. Read the following survey item and identify/explain what might be wrong with it:
“Do you agree that the city council members should not get an increase in their pay?”
4. You read in the newspaper that Proposition Q is favored by 57% of those polled. The results of the survey are said to be accurate within ±2 percentage points using a 95% level of confidence. From the information provided, it can be inferred that the actual population value is probably between ________% and ________%.
5. Explain the importance of “sample size” in research studies.
6. Which specific sampling technique would you use if you wanted each member of the population to have an equal probability of being selected for the sample?
7. To assess the presidential candidate preferences of the registered voters in Maricopa County, AZ, classified by social class and age, a researcher randomly selects voters from each subgroup according to their proportion in the entire county. What is this sampling technique called?
8. A professor of mathematics wants to study how the students in his college perceive the subject. He walks into the college cafeteria and starts asking the students present there if they like mathematics. Which sampling technique is used by the professor in this scenario?
9. In which sampling technique do researchers choose a sample that reflects the numerical composition of various subgroups in a population?
10. In experimental designs, when the effects of the independent variable and an uncontrolled variable are intertwined, so one cannot determine which of the variables is responsible for the observed effect, what is this “uncontrolled” variable know as?
11. List one advantage and one disadvantage of using a pretest-posttest design over using a posttest-only design.
12. Jeanne the Researcher wants to know whether wearing sunglasses improves driving performance. If an independent groups experimental design is used, explain (briefly) how the researcher would conduct this study.
13. Jeanne the Researcher wants to know whether wearing sunglasses improves driving performance. If a within-subjects experimental design is used, explain (briefly) how the researcher would conduct this study.
14. Wendy wants to know if a new sports drink improves physical performance. The number of push-ups each participant can complete in one minute is recorded first. The participants are then given eight ounces of the sports drink, and the number of push-ups completed in one minute is recorded again. Wendy finds that the number of push-ups completed is less after consuming the new sports drink. This finding could be due to the effect of the sports drink (or lack thereof), or it could be due to which type of confound?
15. Explain why you might want to use “counterbalancing” in a repeated-measures (or within-subjects) design.
16. A researcher examined the effect of lighting on learning. Randomly assigned participants learned new material while using a 100-watt or a 105-watt bulb. He found no differences in learning between the two groups. Provide an explanation for why this manipulation may not have found significant results.
17. Explain what is meant by a “floor effect” and a “ceiling effect”.
18. What is meant by the term “demand characteristic” in research studies?
19. What is the difference between a “One-Way” design and a “Factorial Design”?
20. Dunn et al. (2005) conducted an experiment of the relationship between exercise and depression. Participants were randomly assigned to either a low or a high intensity workout regime. Some were assigned to work out 3 days a week, while other participants worked out 5 days a week. Their depression was measured weekly. Identify the independent variable(s) and dependent vaiable(s) in this study.
21. In an experimental design, what is a “Main Effect” and what is an “Interaction”?
22. To examine how a reward influences a desired behavior, a mother first counts the number of times her son makes his bed over a two-week period. For the next two weeks, she gives him a reward every time he makes his bed. Following this period, she stops rewarding him and again counts the number of times he makes his bed. This procedure would be an example of what type of design?
23. Sophia finds that her son Alex enjoys lemon candy. Sophia encourages Alex when he displays courteous behavior at home. A few days later, she then starts reinforcing this behavior with lemon candy at relatives’ homes, and a few days after that, she does this when they are at church. What type of single-case design is Sophia employing with Alex?
24. What is the difference between true experimental designs and quasi-experimental designs?
25. In order to study the effects of watching violent programs on children’s aggressiveness, a researcher observes children’s behavior after they watch 30 minutes of violent programs on television. The researcher concludes that television violence causes aggressiveness. Identify the problem with this study (and the researcher’s conclusion).
26. Provide an example of how “Regression to the Mean” can be a threat to internal validity.
27. In order to study personality development over the lifespan, a researcher studies the same individuals at 7, 14, 21, and 30 years of age. In this case, the researcher is using which type of developmental design?
28. A restaurant is interested in examining the effect of increasing the price of hamburgers on its sales. During the first six months of the year, it measures the number of hamburgers sold each day. It then increases the price and records the number of hamburgers sold each day for the last six months of the year. This quasi-experimental design would be an example of what type of study?
29. Explain “Type I” and “Type II” errors in the context of statistics and hypothesis testing.
30. A researcher was interested in the effect of two different teaching interventions on children’s understanding of science. The researcher measured understanding of science by asking 4th grade children to complete a standardized science test. The researcher first measured the children’s understanding of science on a pretest. Immediately after the pretest, they introduced the two teaching interventions to the children. Half of the children were given a “new” teaching intervention first and an “old” teaching intervention second; the other half was given the “old” teaching intervention first and the “new” teaching intervention second. The researcher administered the same science test again (as a posttest) after each teaching intervention to see if performance was better than the pretest. All children took the pretest, were given both teaching interventions (half given “new” teaching first and half given “old” teaching first), and took the posttest after each teaching intervention. Please answer all of the following questions about this study:
A) In this scenario, what is/are the independent variable(s) (IV)? How many levels are there?
B) In this scenario, what is the dependent variable (DV)?
C) In this scenario, what type of research design is being used? Be as specific as you can.
D) The researchers gave some students the old intervention first and new intervention second, while other students receive the opposite order (i.e., new intervention first, old intervention second). What is this procedure called?
E) What type of statistical test should you use to analyze the results of this study? Why?
