For this assignment, use data from W1 Project.
Data:
Literature Review
Social scientists have long been interested in the accuracy of eyewitness testimony. Several studies over the past few decades have demonstrated that eyewitnesses are not always accurate (e.g., Buckhout, 1974; Bornstein & Zickafoose, 1999). More recently, many individuals have filed appeals based on deoxyribonucleic acid (DNA) evidence. Of those acquitted on this basis, 78 percent had originally been convicted based on strong eyewitness testimony (Stambor, 2006). One reason witnesses may err when recalling information about a criminal is the misinformation effect, which involves "incorporating 'misinformation' into one's memory of the event after receiving misleading information about it" (Myers, 2008). Elizabeth Loftus (1978, 1979a, 1979b, 2001) and her associates have repeatedly demonstrated this effect, finding that memory can be "constructed" based on suggestive questions and information given after the fact. Other factors that play a role in our ability to recall information are decay and stress. Shapiro & Penrod (1986) presented evidence that suggests memory may decay over time, while other researchers have found that as stress increases, the accuracy of recall decreases (Deffenbacher, Bornstein, Penrod, & McGorty, 2004; Payne, Nadel, Allen, Thomas, & Jacobs, 2002).
Hypotheses
Given what we have learned through the literature review, our hypotheses are:
• There will be a relationship between the type of information conveyed (a misinformation effect) and the accuracy of recall about the color of the vehicle.
• Memory may decay over time.
• The level of stress will affect recall.
• There will be a relationship between the level of stress and confidence, such that confidence declines as stress rises.
Method
Participants: You will complete this as a part of your final project. This section should be completed at the end of Week 4.
Procedures
Participants are randomly assigned to one of three levels of stress: high stress, where they are writing a final exam immediately following their participation in the experiment; medium stress, where they are writing a final exam the day following their participation; and low stress, where their participation comes two weeks prior to their final exam. They are shown one of two different versions of a video of a bank robbery and instructed to pay close attention to detail.
All versions share the same beginning scenario, with two individuals entering a bank to rob it. The first individual (individual #1) is 5'10" tall and of medium build, wearing blue jeans, a black leather jacket, and black tennis shoes. This individual is wearing a ski mask with the holes around the eyes large enough for the color of the skin, which is white or light colored, to be visible. The second individual (individual #2) is 6'2" and heavyset, wearing black sweat pants, a red jacket, and dark work boots. This individual is wearing a ski mask identical to that of individual #1. The skin around the eyes is dark. No other skin is visible on either individual. Individual #1 walks to the window and hands the teller a note, bringing up the right hand, which is in the pocket, to simulate a gun. It is unknown whether an actual gun was used. Individual #2 stays back a step as if keeping watch. After the teller gives money to the robber, the two robbers leave the bank, jump into a car waiting at the curb, and drive away. In version #1, the car is blue. In version #2, the car is green.
Following the viewing of the video, each participant meets an individual in the waiting room. This individual (actually a confederate of the experimenter) states that he or she had lost something and had come back to see whether the experimenter found it. The individual begins a conversation about the video and says, "Did you see that blue (or green, depending on the condition) car they were driving?” Half the time, this question is congruent (the color mentioned by the confederate matches the color shown in the video). And half the time, the color is incongruent (the color mentioned by the confederate is different from that visible in the video).
Measures
At the end of this conversation, the confederate leaves, and the participant is asked by the experimenter to complete a short questionnaire to measure his or her memory of the details in the video. This questionnaire consists of fifteen fill-in-the blank questions where participants are asked questions, such as "What kind of pants was the individual who asked for the money wearing?" The participant must write what he or she recalls or "unknown" if uncertain about the response. Each correct answer is given one point, and the points are added to create a continuous measure of recall as the dependent variable. Scores on this measure can range from 0 to 15. This questionnaire is given again two weeks later, and a third time after one month. Participants are also asked to rate their confidence in their recall of each item on a scale of 1 to 10, with one meaning very little confidence and 10 meaning a great deal of confidence. These items are added to create an overall confidence score, with higher scores indicating higher levels of confidence. Scores on this measure can range from 15 to 150.
The misinformation effect is stored in a variable named “recall color.” Recall color is scored as "Correct" if participants correctly identify the color of the car they had seen in the video and "Incorrect" if they incorrectly identify the color.
Finally, all participants complete a short questionnaire to measure their stress levels. This is necessary to check the stress manipulation and ensure it was effective. Possible scores on this measure range from 0 to 25, with higher scores indicating higher levels of stress.
Part 1-In Minitab Express
1.) Choose and run the appropriate descriptive statistics to describe the characteristics of the sample under study (sex, age, and ethnicity) and Recall1, making sure you include:
• A graph
• The appropriate measure of central tendency for your continuous variables
• The appropriate measure of variability for your continuous variables
In Word document
2.) Copy your output tables and graphs to a Microsoft Word document and write a brief, APA-formatted report detailing your findings in the same document as the output. Follow the example given in the lecture on Interpreting Data to format your report.
Example: Participants
There were 72 participants recruited from an introductory psychology class at a University. There were 36 males and 36 females, with 24 Caucasian, 24 African Americans, and 24 other ethnicities represented. The ages ranged from 18 to 62 years, with a mean age of 40.1, SD 12.65.
Part 2 -In Minitab express
1.) Use the appropriate descriptive statistics
2.) Assuming that the sample statistics you computed are exactly equivalent to the corresponding population parameters, identify the following:
a. What score on Recall1 would correspond to an extremely high score?
b. What score on Recall1 would correspond to an extremely low score?"
3.) To find these hypothetical scores, solve for X (your raw score) using the following formula:
X = (±z)(sd) + M, where
z = The z-score cutoff for 5 percent in the tail (±1.645)
sd = Your sample standard deviation
M = Your sample mean
4.) Use Minitab to compute z-scores for Recall1. Complete the table, indicating the appropriate z-scores corresponding to each of the participants whose score is given.
Subject ID Recall at Time 1 Z-score
5 8
10 12
15 10
20 8
25 9
In word document
5.) Write a brief paragraph interpreting these z-scores (e.g., how each individual did in relation to the class in terms of standard deviations and percentiles).
Part 3- In Word Document
1.) Make necessary corrections to your work on the final project and write:
• A comprehensive paragraph describing the participants in the study
• A paragraph describing the major dependent variables of interest (recall and misinformation effect). Be sure to review the Final Project information so you can describe what these variables are, how they were measured, and why they were measured.
ID Sex Ethnicity Age Car Type of Information StressLevel StressScore Recall1 Recall2 Recall3 Confidence Recall Color
1 F L 23 Blue Consistent Low 3 12 10 7 100 Correct
2 F AA 35 Blue Consistent Low 5 6 5 3 112 Correct
3 F AA 21 Blue Consistent Low 2 11 11 9 125 Incorrect
4 F C 42 Blue Consistent Low 9 3 4 2 150 Correct
5 F C 37 Blue Consistent Low 7 8 8 6 136 Correct
6 F AA 26 Blue Consistent Low 4 13 12 9 107 Correct
7 M O 24 Green Consistent Low 3 10 9 7 143 Incorrect
8 M C 19 Green Consistent Low 1 15 13 13 141 Correct
9 M AA 28 Green Consistent Low 4 11 10 8 134 Correct
10 M C 20 Green Consistent Low 2 12 11 9 148 Correct
11 M C 31 Green Consistent Low 5 9 7 5 139 Incorrect
12 M L 22 Green Consistent Low 3 10 9 7 117 Correct
13 F AA 25 Blue Consistent Medium 7 11 9 8 76 Correct
14 F C 32 Blue Consistent Medium 8 5 5 3 99 Correct
15 F C 27 Blue Consistent Medium 11 10 7 5 124 Incorrect
16 F C 36 Blue Consistent Medium 9 4 6 5 83 Correct
17 F AA 24 Blue Consistent Medium 13 7 5 4 105 Correct
18 F L 29 Blue Consistent Medium 10 12 10 7 78 Correct
19 M AA 18 Green Consistent Medium 15 9 8 6 91 Incorrect
20 M C 19 Green Consistent Medium 12 8 8 5 107 Incorrect
21 M L 21 Green Consistent Medium 10 10 9 7 102 Correct
22 M AA 22 Green Consistent Medium 14 4 5 3 120 Correct
23 M C 39 Green Consistent Medium 17 5 4 2 111 Incorrect
24 M O 33 Green Consistent Medium 16 9 7 6 115 Correct
25 F AA 23 Blue Consistent High 17 9 7 5 94 Correct
26 F L 25 Blue Consistent High 18 3 2 2 58 Correct
27 F AA 32 Blue Consistent High 21 8 6 5 73 Incorrect
28 F C 22 Blue Consistent High 19 2 1 1 67 Correct
29 F AA 45 Blue Consistent High 23 5 3 4 81 Correct
30 F C 49 Blue Consistent High 20 10 7 6 92 Correct
31 M C 36 Green Consistent High 25 7 5 5 55 Correct
32 M L 20 Green Consistent High 22 6 5 4 76 Incorrect
33 M C 19 Green Consistent High 17 8 7 7 60 Correct
34 M C 24 Green Consistent High 24 2 6 4 89 Correct
35 M L 27 Green Consistent High 21 3 4 2 72 Correct
36 M AA 24 Green Consistent High 18 7 4 2 78 Correct
37 F C 23 Blue Inconsistent Low 5 11 10 8 97 Correct
38 F L 35 Blue Inconsistent Low 4 7 7 5 107 Incorrect
39 F AA 21 Blue Inconsistent Low 3 12 10 9 120 Correct
40 F C 42 Blue Inconsistent Low 8 5 5 4 146 Incorrect
41 F O 37 Blue Inconsistent Low 9 9 8 6 132 Incorrect
42 F C 26 Blue Inconsistent Low 3 12 11 9 103 Correct
43 M L 24 Green Inconsistent Low 4 12 10 8 138 Incorrect
44 M AA 19 Green Inconsistent Low 3 8 7 5 136 Correct
45 M C 28 Green Inconsistent Low 2 11 11 9 132 Correct
46 M AA 20 Green Inconsistent Low 6 9 9 7 143 Incorrect
47 M C 31 Green Inconsistent Low 4 10 9 7 134 Incorrect
48 M C 22 Green Inconsistent Low 4 11 10 9 114 Correct
49 F AA 25 Blue Inconsistent Medium 6 10 8 8 75 Incorrect
50 F L 32 Blue Inconsistent Medium 9 4 3 3 96 Incorrect
51 F C 27 Blue Inconsistent Medium 13 9 7 6 121 Correct
52 F AA 36 Blue Inconsistent Medium 8 5 4 4 80 Incorrect
53 F C 24 Blue Inconsistent Medium 12 6 4 3 102 Incorrect
54 F C 29 Blue Inconsistent Medium 11 11 10 8 75 Correct
55 M C 18 Green Inconsistent Medium 14 8 8 7 89 Incorrect
56 M AA 19 Green Inconsistent Medium 13 7 6 4 104 Correct
57 M C 21 Green Inconsistent Medium 16 9 7 6 99 Incorrect
58 M C 22 Green Inconsistent Medium 15 5 5 3 117 Correct
59 M L 39 Green Inconsistent Medium 11 4 4 4 109 Incorrect
60 M AA 33 Green Inconsistent Medium 15 8 6 5 112 Incorrect
61 F C 23 Blue Inconsistent High 18 7 5 4 93 Correct
62 F AA 25 Blue Inconsistent High 16 1 1 0 59 Incorrect
63 F C 32 Blue Inconsistent High 20 7 5 4 71 Correct
64 F L 22 Blue Inconsistent High 21 3 3 2 68 Incorrect
65 F O 45 Blue Inconsistent High 22 6 4 3 79 Correct
66 F AA 49 Blue Inconsistent High 21 8 5 4 94 Incorrect
67 M C 36 Green Inconsistent High 25 5 4 3 54 Incorrect
68 M AA 20 Green Inconsistent High 23 4 4 2 77 Correct
69 M
L 19 Green Inconsistent High 19 6 5 3 62 Incorrect
70 M AA 24 Green Inconsistent High 23 0 1 0 87 Incorrect
71 M C 27 Green Inconsistent High 22 5 5 3 70 Correct
72 M L 24 Green Inconsistent High 17 3 3 1 76 Incorrect
To analyze the characteristics of the sample and the Recall1 variable using Minitab Express, follow these steps:
Part 1 - Descriptive Statistics:
1. Open Minitab Express.
2. Go to "File" and click on "Open Worksheet."
3. Select the data file that contains the participant information and Recall1 scores.
4. Once the data is imported, go to "Stat" and click on "Basic Statistics."
5. In the "Variables" section, select the variables 'Sex', 'Ethnicity', 'Age', and 'Recall1' by clicking on them while holding the Ctrl key.
6. Click on the "Graphs" tab and select the appropriate graph type (e.g., bar chart for sex and ethnicity, histogram for age, etc.).
7. Click on the "Options" tab and check the boxes for "Mean" and "Standard Deviation."
8. Click on "OK" to generate the output tables and graph.
Part 2 - Hypothetical Scores and Z-Scores:
1. Based on the information provided, you need to calculate the hypothetical scores that correspond to extremely high and low scores on Recall1.
2. Use the following formula:
X = (±z)(sd) + M
where
±z = Z-score cutoff for 5 percent in the tail, which is ±1.645
sd = Sample standard deviation of Recall1
M = Sample mean of Recall1
3. Calculate the hypothetical high and low scores using the formula for each condition (high, low) separately.
4. Use the formula in Minitab Express to calculate z-scores:
a. Click on "Calc" and then "Standardize."
b. Select the variable 'Recall1' and click on the "Options" button.
c. In the "Standardization" section, select the "Standardize using" option and enter the sample mean and standard deviation for Recall1.
d. Click on "OK" to calculate the z-scores.
Part 3 - Participant Description and Variable Description:
1. In a Word document, provide a comprehensive paragraph describing the participants in the study, including their demographics (Sex, Ethnicity, Age) and any other relevant information mentioned in the data