Group Projects: June 8, 2006

Relationships Between Categorical Variables

In this project we will be studying the relationship between Men and Women and if they watch American Idol or not. Our sample will be a sample of convenience, the students in this classroom. Each student will write on a piece of paper if they are a male or a female (this should be a pretty easy question to answer) and “Yes” or “No” if they watch American Idol (here watch is defined as do you watch it frequently not just tuning into the final episode). We will then collect the data and analyze it using JMP IN.

Once the data has been collected we must enter it into JMP:

1)First to open JMP IN on the computer click on START\Programs\Mathematics and Stat\JMP IN 5.1\JMP IN 5.1.

We will then be creating a new data table so under the JMP starter click on NEW DATA TABLE.

2)To load our data, on the left hand side of the screen under columns, right click on column 1and select COLUMN INFO. Name the column “Sex”, change the data type to Character, and the Modeling to Nominal, then click OK.

3)You must now begin filling down the column, the sex data (M for male F for female). Make sure not to make any mistakes when entering the data.

4)Repeat the above steps by right clicking on “Sex” and then choosing New Column and name this one “Amer. Idol”, change the Data Type to Numeric and the Modeling Type to Nominal. Fill in this data but make sure that you pair the “Amer. Idol” with the correct sex (the person’s sex should be placed directly across from their Amer. Idol variable in the table!!!) Fill in the table by typing in a 0 if they said “no” and a 1 if the student said “yes”

Now we can analyze the data using JMP.

1)On the top toolbar click on ANALYZE\Fit Y by X

2)When the new screen comes up we want to click on “Amer. Idol” and then the Y,Response button. This will make “Amer. Idol ” our y-variable in our cont. table.

3)Now click on “Sex” and then the X,Factor button. This will make “Sex” our x-variable in our cont. table.

4)You should see a contingency table of the two variables. Copy and Paste the table below, does it seem that a larger percentage of females or males watch American Idol?

5)Compute by hand the chi-squared statistic for the class data by filling in the observed and expected counts in the following table, and then computing the

(Observed-Expected)2/Expected for each cell. (The observed values are the top numbers in each

cell)

Men / Women / Totals:
Watch Amer. Idol / Observed:
Expected: / Observed:
Expected:
Do not watch Amer. Idol / Observed:
Expected: / Observed:
Expected:
Totals:

6)You can then check your answer by looking under Tests and then find the Pearson test. This should give you the Chi-Square statistic and the p-value (Prob>ChiSq). Write what both of these are below:

Chi-Square Statistic:

P-value:

7)When we are performing this hypothesis test what is the null and the alternative hypothesis?

Null Hyp:

Alternative Hyp:

8)Based on the p-value you found would you accept or reject the null hypothesis? Write one sentence to conclude your findings on if there is a relationship between sex and watching American Idol.