Question: An investigator had data relating the period of time from menarche until first childbirth and breast cancer for 13,465 women. The investigators set up a case-control study. In the following distribution of data, the data in Table 10.1 on page 357 have been arranged so that data for breast cancer status are in the columns and data for age-at-first birth are in the rows.

RQ: Is there a relationship between the age at age of first childbirth and breast cancer?

Step 1: A. Create Variables

? Start SPSS.

? Click the Variable View Tab.

? Enter the variables BreastCA,

? Click the Values cell column.

a. Click the push button ellipsis to open the Values Label box.

b. Enter 1 to the right of Value and enter 1 = Yes. Click Add. Enter 2 to the right of Value and enter 2 = No. Click Continue.

B. Repeat the process with the variable AgeFirstBirth with 1 = 30 or more years and 2 = Under 30 years. Click OK.

C. Enter the variable Frequency as a numeric variable.

Step 2: Create the Data

? Click the Data View tab.

? Enter the values.

Step 3: Analyze the Data

A. From the menu bar, select Data> Weight Cases.

B. The Weight Cases dialog box opens; select weight cases by Frequency by moving frequency into the Frequency Variable box.

C. Click OK.

D. The Crosstabs dialog box opens;

a. Select AgeFirstBirth and move it into Row (s) box.

b. Select BreastCA and move it into Column(s) box.

c. Click the Statistics button; in the Crosstabs: Statistics dialog box, click Chi-square, Risk, and Cramer's V.

d. Click Continue.

e. Click Cells: under Counts, select Observed and Expected and under Percentages select Row.

f. Click Continue.

g. Click OK.

Step 4: Interpret the Results

Chi square [continuity correction] =

Odds Ratio = and 95% Confidence Interval =

Summary of Results in APA Format: