CJ 161 STATISTICS IN CRIMINAL JUSTICE SP 01
LAB 8       4/19/01 DUE 5/7/01 4:30 PM

PURPOSE: The purpose of this lab, and the associated paper, is for you to engage in hypothesis testing using the t test of mean differences for independent samples. WE WILL NOT HAVE LAB TIME LINKED WITH THIS SO YOU NEED TO CARRY OUT THE SPSS WORK ON YOUR OWN. The exercise examines the impacts of being African-American, vs. not, on confidence in the criminal justice system.

THE DEPENDENT VARIABLE: CONFICJS. You have the syntax to create this variable in LAB 6. If you saved the data file from this lab you already have that variable on your data file. You want to look carefully at the questions that make up this index (to learn more about indexes take 160) and be sure you know what a HIGH score means and what a LOW score means.

THE INDEPENDENT VARIABLE is called AFRAM. This is on the class data file.
0= NOT African-American; 1 = African-American.

THE LAB

1. Download the class data file CJ161EE.SAV - it is linked to the topics page: http://www.rbtaylor.net/161sp01topics.htm
   

2. Run the syntax from the LAB 6 assignment, as needed, to create the dependent variable.
   
3. Run the t test for independent samples. READ K&F PAGES 31-35. Put in AFRAM as the grouping variable. The scores on the variable are 0 and 1.
   
4. Save your output

THE SCENARIO
Imagine that these data come from a representative sample of criminal justice majors enrolled on the main campus for the Spring 01 semester. You are interested in learning if African-American criminal justice majors have more or less confidence in the criminal justice system than do non-African-American cj majors. You select an alpha level of p < .01 and a two tailed test for finding your t-critical. (HINT - the value you want is + / - 2.70.)

THE PAPER

PARAMETERS
No more than two pages, typed, double spaced, although references may appear on a third, extra page. SSN only on the top of each page. No names anywhere.
PAGE 1
   1. State the null hypothesis - one sentence
   2. State the alternate hypothesis - one sentence
   3. State whether t observed is greater than t critical or less than t critical - one sentence
   4. State whether you reject or fail to reject the null hypothesis - one sentence.
   5. State in nontechnical terms what you have learned. You can speculate on the REASONS for what you have found, but I am most interested in a nontechnical description of what you have learned. NO MORE THAN HALF A PAGE
   6. Attach your printout.
NO MORE THAN ONE PAGE, TYPED, DOUBLE SPACED. SSN ONLY AT TOP. NO NAMES. WE WILL STOP READING AT THE BOTTOM OF PAGE 1!!

 THE GRADING

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50%	5
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