Stats >> Training >> Stats #02: Practice Exercises

These exercises refer to three data sets:

• BF.SAV, a study of breast feeding in pre-term infants;
• HOUSING.SAV, a study of housing prices in Albuquerque.

You should have both files on a floppy disk, which is attached to your handout.

1. For the breast feeding data, compute a frequency table for all the values (not just the first ten) of the mother's medical record number. Verify that no mother of triplets was included in this study.

2. For the breast feeding data, compute a frequency table for the infant's medical record number. Confirm that no infant appears twice in this study.

3. Open the file HOUSING.SAV. How many houses are in this sample?

4. An important portion of the breast feeding study is an examination of side effects of the treatment. Some of the important side effect variables are:

• Sepsis (SEPSIS),
• Total apnea and bradycardia incidents (TOTAL_AB),

The first variable in this list is categorical and the second is continuous. Compute and interpret frequencies and ranges as appropriate for these of these variables.

5. Other important variables in this study are breast feeding status at discharge (BF0), three days after discharge (BF1), three months after discharge (BF3), and six months after discharge (BF4). All of these variables are categorical. Summarize these variables using frequency tables. Note: BF2 refers to breast feeding status six weeks after discharge, but because this variable was not evaluated prospectively, the researchers decided not to include it in any analysis.

6. In the housing data set, three important variables are the size of the house (SQFT), whether the house was custom built (CUST) and the sales price of the house (PRICE). Which of these variables are continuous and which are categorical? Summarize the continuous variables using frequencies and ranges as appropriate.

7. In the breast feeding study, examine the relationship between the treatment group (FEED_TYP) and all of the side effect variables discussed above.

8. In the breast feeding study, examine the relationship between the breast feeding at discharge (BF0) and the treatment group (FEED_TYP), Mother's age (MOM_AGE), type of delivery (DEL_TYPE), birth weight (BW), gestational age (GEST_AGE), one and five minute Apgar scores (APGAR1, APGAR5), and age at discharge (DC_AGE).

9. In the housing study, examine the relationship between sales price (PRICE) and all other variables in the data set.

10. In the housing study, examine the relationship between whether a home was custom built (CUST) and whether it is more likely/less likely to be found on a corner lot (COR) or in the northeast region of the city (NEC).