Question

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.

Group Responses to Car Speed Hit v. Smashed
Hit Group	Smashed Into Group
32	50
26	44
40	54
23	45
42	44
20	40
37	49
25	34
24	38
22	30
19	50
24	46
19	40
22	35
29	43
24	41
34	30
33	39
37	44
20	35

Your job is to determine if smashed into group reports higher speed than hit group. I suggest you start by calculating the means and standard deviations for each group.

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Question 1

Select the null hypothesis

Group of answer choices

Ho: Smashed into group estimated lower or same speed than hit group (directional hypothesis)

Ha: Smashed into group estimated higher speed than hit group

Question 2

Select the alternative hypothesis

  

Group of answer choices

Ha: Smashed into group estimated higher speed than hit group

Ha: Smashed into group estimated lower or same speed than hit group

Question 3

What is the risk level?

Group of answer choices

.25

.5

.01

.05

Question 4

What is the best statistical test to use?        

Group of answer choices

z-test

correlation test

t-Test for dependent samples

t-Test for independent samples

Question 5

Compute the test statistic. The formula is below for you. Also, remember to use the variance rather than the standard deviation in your calculation. Which of the following is the value of the test statistic you computed?

Group of answer choices

5.45

2.67

2.50

13.59

6.30

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Question 6 1 pts

Now it's time to compare our obtained value (the one you just calculated) to the critical value. First, we'll need the degrees of freedom. What are the degrees of freedom?

Group of answer choices

38

39

19

40

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Question 7 1 pts

Should we use a "one tailed" or a "two tailed" test for this? To figure this out, think about whether it is directional or non-directional.

Group of answer choices

one tailed

two tailed

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Question 8 1 pts

What is the critical value for this statistical test? (hint: you'll need your answers to the previous two questions, as well as your "level of risk" to find this answer in the table in the back of your Salkind textbook; remember, if the exact degrees of freedom aren't in the t-test table of critical values, you can choose the closest DF that is there).

Group of answer choices

1.69

1.56

2.42

2.02

Question 9

Based on your answer to the previous question, what is your decision?

Group of answer choices

Fail to reject the null hypothesis

Reject the null hypothesis

Question 10

What does this all mean? (choose the best interpretation for the findings from this study).

Group of answer choices

The group that was told the cars "smashed into" each other reported significantly slower speeds than the group that was told the cars "hit" each other.

The group that was told the cars "smashed into" each other reported significantly faster speeds than the group that was told the cars "hit" each other.

The group that was told the cars "smashed into" each other reported similar speeds to the group that was told the cars "hit" each other

Question 11

Write up your results as you would see them in an APA style research paper. Remember to report the means and standard deviations for each group!

Answer 1

Questions 1

Null hypothesis

H0: Smashed into group estimated higher speed than hit group.

Alternative hypothesis

Ha: Smashed into group estimated smaller speed than hit group.

Questions 2

Null hypothesis

H0: Smashed into group estimated higher speed than hit group.

Questions 3

Level of significance =0.05

Questions 4

Correlation test use for testing smashed and hit group.

Questions 5

Null Hypothesis: H₀: ρ = 0A

lternate Hypothesis: H_a: ρ ≠ 0

Test Statistic:

The formula for the test statistic is t=r√n−2/√1−r2

Value of test Statistic = 1.78

Questions 6

Degrees of freedom = 19

Questions 7

One tailed test

Questions 8

Table value = 1.729

Questions 9

Here we reject Ho

Questions 10

The correlation between the smashed and hit group.