# Review of Inference in Case CQ

## Introduction

Review from 6052 Materials:

SAS Tutorials:

Useful SAS Procedures:

• PROC TTEST
• PROC NPAR1WAY
• PROC GLM
• PROC MEANS
• PROC SGPLOT

## PHC 6053 Video (6:56)

Now try working through a few of these methods with the NHANES data on your own.

## EXAMPLE: NHANES DATA – Inference in Case CQ

• Dataset: nh_2000a.sas7bdat – To use the dataset, save the file into the folder on your computer which is associated with a SAS library. Once you do this, open SAS and you should be able to immediately access the file using that library and the file name.
• SAS Code and Output: Unit1-InferenceCaseCQ.pdf

## LEARN BY DOING

Answer the following using the output provided above for this example.

• When comparing SBP between males and females:
• Would we use the equal-variances or unequal-variances t-test?
• What is the t-value associated with the appropriate t-test?
• Provide a specific and accurate interpretation of the appropriate confidence interval for the difference in population means.
• When comparing height between males and females:
• Would we use the equal-variances or unequal-variances t-test?
• What is the t-value associated with the appropriate t-test?
• Provide a specific and accurate interpretation of the appropriate confidence interval for the difference in population means.
• Due to the sample sizes involved, we are not concerned with normality of the populations being compared, however, which of the outcome variables considered here (SBP, HTIN, WTLBS) has a distribution which is reasonably normally distributed in the two gender groups.
• State the conclusion to the one-way ANOVA comparing SBP between the three smoking groups.

Solution: Unit1-InferenceCaseCQ-Solution.pdf