O 2 A OSearch Discussion #11-How Fast -Fall 19.docx AutoSave osvaldo lima OL Insert References Share File Home Design Layout Mailings Review View Help Comments 1 1 I 2 I 3 I 4 5 6 7. L That is, the average speed of "smashed into" group is significantly higher than the "hit group are equal PSY 3211 Research Methods and Design I-Discussion #11- How Fast? Instructions: In 1974, Loftus and Palmer conducted a classic study demonstrating how the language used to ask a question can influence eyewitness memory. In the study, college students watched a film of an automobile accident and then were asked questions about what they saw. One group was asked, "About how fast were the cars going when they smashed into each other?" Another group was asked the same question except the verb was changed to "hit" instead of "smashed into." The "smashed into" group reported significantly higher estimates of speed than the "hit" group. You, as a researcher wonder if Loftus and Palmer's study is reliable and repeats this study with a sample of FIU students and obtains the following data 2. Tell me your level of risk The level of risk will be 05 Hit Group Smashed Into Group 3. Determine the best statistical test to use 28 46 22 41 Since we are looking at two groups, the best test statistic to use is the t-Test for 36 51 independent samples. 32 36 38 41 4. Compute the test statistic. (Note: You can use the table below to help you calculate your SD, which will be important later when you write up your means and SDs)! 39 37 33 46 X-M (х- М) 37 31 (X-M X-м Hit Smashed 32 35 Into 25 52 12.6025 28 -3.3 10.89 46 3.55 2.1025 22 55 22 -9.3 4.7 86.49 41 -1.45 8.55 -6.45 27 50 36 32 38 22.09 51 73.1025 41.6025 0.49 22 41 0.7 6.7 36 44.89 41 -1.45 2.1025 29.7025 12.6025 131.103 25 39 -5.45 7.7 59.29 39 37 32 47 33 1.7 2.89 32.49 46 3.55 26 45 37 5.7 31 35 -11.45 -745 36 32 32 0.7 0.49 55.5025 35 41 91.2025 25 -6.3 39.69 52 9.55 46 39 22 -9.3 86.49 55 12.55 157.503 40 37 27 4.3 18.49 50 7.55 57.0025 86.49 39.69 -1.45 -3.45 22 -9.3 2.1025 41 39 Your job is to determine if smashed into group reports higher speed than hit group. As you work on this problem, make sure to provide information for each of the eight steps we cover in Chapter 11 (Salkind) as well as the APA write-up you would see in a results section 11.9025 25 -6.3 32 0.7 0.49 47 4.55 20.7025 26 -5.3 28.09 45 2.55 6.5025 36 4.7 22.09 32 41 46 -10.45 109.203 2.1025 12.6025 29.7025 1. State the null and alternative hypotheses Null Hypotheses H0 μ1- μ2 That is, the average speed of "smashed into" group and hit" group are equal. 13.69 59.29 35 3.7 7.7 -1.45 39 3.55 40 626 8.7 75.69 37 -5.45 849 860.95 M- 31.3 42.45 n-1 Variance 19 19 38.4316 6.19932 45.31315789 Alternative Hypotheses H1: l2 SD 6.731504876 Focus Page 1 of 4 47 of 901 words 100% 1:07 PM PC AutoSave Off ) A OSearch Discussion #11 - How Fast -Fall 19.docx osvaldo lima OL Insert References Help Share File Home Design Layout Mailings Review View Comments 1 1 I 2 3 I 4 I 5. I 6 7 . 9. Finally, write up your results as you would see it in a results section of an empirical research paper. Make sure to include the means and SDs for smashed into and hit group (in miles). I do NOT need to see the effect size (Cohen's D) 5.45 5. Determine the value needed to reject the null hypothesis. Remember to calculate the correct degrees of freedom before finding the critical t-value! Note whether it is best to 10. Was your obtained t-value positive or negative? Would it matter either way? With your discussion group, tell my why a positive or negative value is not important when it comes use the one-tailed or two-tailed test. to your obtained value The value needed to reject the null hypothesis is 5.45. The degree of freedom for finding the critical value (tm-2) 20+20-2 11. What is more appropriate to use for your data set: the one-tailed 1-Test or the two-tailed - =38 Test. Why? Would your APA write-up differ depending on which you used? The level of significance is not provided so it can be assumed as 0.05 The critical value at level of significance 0.05 with 38 degree of freedom from the t-value table (one tailed) is 1.686. 12. Why would it be easier to find significance using ap value of 05 than a p value of .01? 6. Compare the obtained and critical value The obtained value t is 5.45 and the critical value is to2, al#n2.2 = 1.686 13. Finally (and this is the tough one), how would your results have differed with regard to steps 4 through 9 if you had used n rather than n-1? The obtained value is greater than the critical value.. 7. Decide whether you will retain the null hypothesis or As, the absolute value oft is greater than the t critical value, so the null hypothesis is rejected. Thus, it can be decided that it would not retain the null hypothesis and the "smashed into" group report higher estimates of speed than the "hit" group. 8. Decide whether you will reject the null hypothesis As, the absolute value of t is greater than the t critical value, so the null hypothesis is rejected. Thus, it can be decided that it would not retain the null hypothesis and the "smashed into" group report higher estimates of speed than the "hit" group. DFocus 47 of 901 words 100% Page 4 of 4 1:12 PM PC