Assignment 3 CONFOUNDS PSYC 227 10 points SCENARIO 1 Ms

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Assignment 3 CONFOUNDS

PSYC 227

10 points

SCENARIO 1

Ms. Connors’ third-grade class at Emerald Elementary School is having difficulty learning how to divide numbers. On homework problems and class exercises they seem to be struggling with division. So, Ms. Connors develops a new approach to teach division that relies heavily on real-world examples rather than abstract numbers on the chalkboard. She decides to test the effectiveness of this new method. In the first week of April she gives her entire class a math exercise to perform that consists entirely of division problems. Overall, the children can answer about 45% of the questions correctly. For the next month Ms. Connors uses her new method to teach division to the children. Then she gives them a posttest that consists of division problems similar in difficulty to the problems on the pretest. Ms Connors did not go over the answers to the pretest with the children and it is unlikely that the children would remember the specific questions a month later. She finds on the posttest that the children, on average, answer 61% of the items correctly. Ms. Connors is pleased and concludes that her new teaching method works well.

1. Identify the independent variable:

   1. Dimension:

1. 1. Level 1:

1. 1. Level 2:

1. Identify the dependent variable and identify the unit of measure when available.

1. Identify at least one control variable.

1. Identify one experimental confound in this study if one is present.

1. If present, how should the researcher conduct this experiment without an experimental confound?

SCENARIO 2

Dr. Adams believes that enhancing people’s physical fitness will increase their self-esteem. She conducts a study. In week one of the spring quarter, 300 PSYC 101 students complete a psychological test that measures self-esteem (1 – 30; higher score = higher self-esteem). Based on their scores, Dr. Adams asks the 25 students who have the lowest self-esteem scores whether they would participate in an 8-week study on “Physical Fitness”. Students receive extra credit for participation. Most students (22) say “yes”. Their physical fitness is measured and then, for 8 weeks, this group meets twice a week to do stretches, aerobic activities (e.g., treadmill) for 1 hour, then participate in a team sport (e.g., volleyball, basketball). Participants’ physical fitness and self-esteem are measured again at the end of the program. The data analysis reveals a significant mean increase in fitness and self-esteem. Should we conclude from this study that increased physical fitness caused an increase in participants’ self-esteem?

1. Identify the independent variable:

   1. Dimension:

1. 1. Level 1:

1. 1. Level 2:

1. Identify the dependent variable and identify the unit of measure when available.

1. Identify at least one control variable.

1. Identify one experimental confound in this study if one is present.

1. If present, how should the researcher conduct this experiment without an experimental confound?

SCENARIO 3

A week ago, Dr. Tamuri and his large research team finished conducting a sleep survey using a randomly selected sample of 200 adults in the Los Angeles area. Each adult was interviewed by phone, and it took only 3 days to collect all the data. Today, by chance, a massive earthquake hits the L.A. area. Dr. Tamuri receives permission from his university’s Institutional Review Board to re-interview the participants in order to find out how people’s sleep changes following a major traumatic event. Starting a week after the earthquake, the same participants are interviewed again. Again it took 3 days to collect all the data. Of the original 200 participants, 120 agree to complete the interview again. Among these 120, the findings reveal many statistically significant changes. For example, after the earthquake, the frequency of participants’ nightmares increased and, overall, they reported having more trouble falling asleep when they went to bed.

1. Identify the independent variable:

   1. Dimension:

1. 1. Level 1:

1. 1. Level 2:

1. Identify the dependent variable and identify the unit of measure when available.

1. Identify at least one control variable.

1. Identify one experimental confound in this study if one is present.

1. If present, how should the researcher conduct this experiment without an experimental confound?

SCENARIO 4

Before the start of a school year, a company donates 100 computers to Pine Elementary School with the hope that this will improve students’ learning. Prior to this, the school – which is located in a lightly populated and economically impoverished region – did not have student computers. Dr. Lopez, and educational psychologist, is asked to assess whether the computers produce an educational benefit. She develops a set of math and verbal tests and administers them to 5th and 6th graders at Pine at the start and end of the school year. She also gets permission from Starbird Elementary School to give the same tests to its 5th and 6th graders at the start and end of the school year. Starbird is the closest school to Pine although it is 40 miles away and located in a region that consists of mostly middle-income families. The results show that the children at Pine, despite having computers, showed overall math and verbal gains similar to those at Starbird. Should we conclude that the computers failed to improve student learning?

1. Identify the independent variable:

   1. Dimension:

1. 1. Level 1:

1. 1. Level 2:

1. Identify the dependent variable and identify the unit of measure when available.

1. Identify at least one control variable.

1. Identify one experimental confound in this study if one is present.

1. If present, how should the researcher conduct this experiment without an experimental confound?