Quantitative Analysis for Criminal Justice

This second part requires analysis and interpretation, and you will submit an Excel file and a Word document for this Assignment

 

Examination Part II

Instructions: Complete the following questions. Enter answers and explanations in this document. Show calculations in an Excel file, using a separate worksheet (tab) for each question.

  1. Skills and self-esteem are believed to influence job performance. To investigate this, an experimenter split 14 recent parolees into “high skill and self-esteem” and “low skill and self-esteem” groups. Three months later, employers were asked to rate each parolee’s job performance on a standard test that gives ratings from 1 to 10, with 10 being the highest. The following ratings were obtained for the individuals in the two groups:
High skills and self-esteem Low skills and self-esteem
9 6
6 5
3 5
8 4
7 4
7 5
9 6

 

  1. Run descriptive statistics on the data. Please provide measures of central tendency and variability for the entire sample and also by groups.
  2. Are there differences in job performance between the two groups? In your response, provide the following:
  • The test you will run
  • The null and research hypothesis
  • The test results
  • Your interpretation of the results
  1. Some researchers contend that anxiety is detrimental to performance, while others argue that anxiety actually enhances performance. To answer this question once and for all, Dr. Rylee has each subject in an experiment work on crossword puzzles before and after being exposed to an anxiety-inducing stimulus (a segment from a Friday the 13th movie). She measured the number of words completed by each subject. The data from her subjects are presented below. Using α = .05, test the null hypothesis that the two groups do not differ.
No Anxiety Anxiety
Pamela 23 14
Scott 19 11
Megan 21 10
Andrea 23 11

 

Provide the following in your answer:

  • The test you will run
  • The null and research hypothesis
  • The test results
  • Your interpretation of the results
  1. A researcher is interested in the effects of family size on delinquency for a group of offenders and examines families with one to four children. She obtains a sample of 16 families, four of each size, and identifies the number of arrests per child for delinquency. The data are as follows:
Group 1 Group 2 Group 3 Group 4
4 children 3 children 2 children 1 child
n = 4 n = 4 n = 4 n = 4
10 8 5 4
8 8 6 5
9 6 7 2
10 9 9 2

 

Test the hypothesis that the groups are different. In your answer address the following:

  • The test you will run
  • The null and research hypothesis
  • The test results
  • Your interpretation of the results
  1. On his morning commute, a researcher notices that the shorter the interval of time between traffic light changes, the more vehicles run the red light. Interested in this relationship, the researcher conducts an experiment over the next few weeks. Each morning, first he chooses a traffic light at random. Once the light changes, he begins counting the number of vehicles running red lights. He continues to count until the light changes again. The data on six lights are as follows:
Length of Light (X) Number of Cars (Y)
10 20
13 19
19 17
25 11
28 9
30 8

 

  1. Show the results of the regression.
  2. Calculate the regression line.
  3. What is the slope?
  4. If the length of a light is seven seconds, how many cars would you predict would run the red light?
  5. Calculate Pearson’s r for the following set of data:
A B
3 8
5 9
7 10
9 11
11 10
13 9
15 8

 

 

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