## PSYC 3111

## Final Extra Credit

## Worth up to 20 points

Use the text listed below, which is adapted from Loftus and Palmer (1974), to answer the following questions.

· The number of extra credit points you earn will be determined by the number of your fully correct answers.

· You may not work with other students on this assignment, and you may not ask Dr. Stratford or one of the TAs for any section of PSYC 3111 for help with this assignment.

· Please upload your answers, as a single pdf, to the ‘Final Extra Credit’ dropbox on D2L. All answers must be submitted before our last day of class

1. What is the general theory of which this study is a part? (1 pt)

2. What is the study’s stated hypothesis? (1 pt)

3. What two cycles of research are represented in this study? (2 pts; 1 pt each)

4. How many variables are used in this study? (1 pts)

There are 2 variables(IV and DV)

5. If there are two or more variables, what is/are the IV(s)/Predictor(s) and DV(s)/Outcome(s) variable? (2 pts)

6. On what scale of measurement is/are the variable(s) measured? (1 pt)

7. Is/are the variables continuous or discrete (1 pt)?

8. What question(s) would you ask to evaluate this study’s construct validity? (1 pt)

9. What question(s) would you ask to evaluate this study’s external validity? (1 pt)

10. Suppose the data file attached to the ‘Final Extra Credit’ dropbox (called ‘PSYC 3111 EC Data.xlsx) represents the data obtained from this study. Given the number of type of variables in this study, which statistical test is the most appropriate to run to evaluate the statistical validity of this study? (1 pt)

11. Run the statistical test described in # 10 above in R Studio. Copy and paste the printout you receive from R Studio below (2pts).

12. Make a graph that would be most appropriate to represent the findings of this study, given the number and type of variables in this dataset, using any statistical software you would like (2 pts).

13. Based on these results, what do you conclude (does the data support or refute the proposed hypothesis)? How do you know? (2 pts; 1 pt for each answer)

14. Write up these results in proper APA format, including not only the formulaic format (such as r(df) = r-coefficient, p-value), but also a description of what these results indicate. (2 pts; 1 pt for each answer)

There is significant different between Hit and Smashed. T(88)= -42.78, p<

How accurately do we remember the details of a complex event, like a traffic accident, that has happened in our presence? More specifically, how well do we do when asked to estimate some numerical quantity such as how long the accident took, how fast the cars were traveling, or how much time elapsed between the sounding of a horn and the moment of collision?

It is well documented that most people are markedly inaccurate in reporting such numerical details as time, speed, and distance (Bird, 1927; Whipple, 1909). For example, most people have difficulty estimating the duration of an event, with some research indicating that the tendency is to overestimate the duration of events which are complex (Block, 1974; Marshall, 1969; Ornstein, 1969). The judgment of speed is especially difficult, and practically every automobile accident results in huge variations from one witness to another as to how fast a vehicle was actually traveling (Gardner, 1933). In one test administered to Air Force personnel who knew in advance that they would be questioned about the speed of a moving automobile, estimates ranged from 10 to 50 mph. The car they watched was actually going only 12 mph (Marshall, 1969, p. 23).

Given the inaccuracies in estimates of speed, it seems likely that there are variables which are potentially powerful in terms of influencing these estimates. The present research was conducted to investigate one such variable, namely, the phrasing of the question used to elicit the speed judgment. Some questions are clearly more suggestive than others. This fact of life has resulted in the legal concept of a leading question and in legal rules indicating when leading questions are allowed (Supreme Court Reporter, 1973). A leading question is simply one that, either by its form or content, suggests to the witness what answer is desired or leads him to the desired answer.

In the present study, subjects (45 students) were shown films of traffic accidents and then they answered questions about the accident. The subjects were interrogated about the speed of the vehicles in one of two ways. Some subjects were asked, “About how fast (in terms of speed) were the cars going when they hit each other?” while others were asked, “About how fast (in terms of speed) were the cars going when they smashed into each other?” As Fillmore (1971) and Brantford and McCarrell (in press) have noted, hit and smashed may involve specification of differential rates of movement. Furthermore, the two verbs may also involve differential specification of the likely consequences of the events to which they are referring. The impact of the accident is apparently gentler for hit than for smashed.

Loftus, E. F., & Palmer, J. C. (1974). Reconstruction of automobile destruction: An example of the interaction between language and memory.Journal of verbal learning and verbal behavior, 13(5), 585-589.)