Hypothesis Testing/Central-Limit Theorem

SOSC341 Understanding Statistical Inference

Assignment    Hypothesis Testing/Central-Limit Theorem

Assignment

 

In a classic study of human memory, Elizabeth Loftus (1975) asked two groups of subjects to watch a very short film of a traffic accident (the film itself lasts less than a minute, and the accident only a few seconds). In the film, a car runs a stop sign into oncoming traffic, ultimately causing a five-car, chain-reaction accident.

 

The two groups were then given a questionnaire with 10 questions on it. For each group, only two questions were targets; the rest were just filler. For Group 1, the first target question was “How fast was car A (the car that ran the stop sign) going when it ran the stop sign?” Group 2 was asked: “How fast was car A going when it turned right?” Both groups received the same final question on the form, which was “Did you see the stop sign for car A?”

 

For the target question about the speed of the car.  Consider what the study is measuring (the dependent variable)

 

The null hypothesis (in words) would be:

 

The alternative hypothesis (in words) would be:

 

The null and alternative (in symbols) would be:

 

Null =

 

Alternative = ____________________.

 

 For each of the following samples, use the available information to calculate (where possible) or predict the following statistics:

 

 (standard deviation)

 

For all three samples,

 

Sample 1

 

2

 

3

 

2

 

5

 

3

 

3

 

4

 

3

 

4

 

4

 

 Sample 2

 

Stem     Leaf

 

0              7

 

1              2, 3, 7, 7

 

2              8, 9, 9

 

3             

 

4              0, 1

 

 

 

Sample 3

 

 = 50

 

 = 1,270.533

= 33,706