# Learn by Doing – Proportions (Step 2) Valid or Invalid Sampling?

Published: October 22nd, 2013

Category: Activity 1: Learn By Doing

We are conducting a survey to determine if an upcoming bond measure will receive a majority vote in the county. The null hypothesis claims that p = 0.50, where p is the proportion of registered voters in the county who say they support the bond measure.

http://phhp-faculty-cantrell.sites.medinfo.ufl.edu/files/2013/10/LBD_12020_prop2.swf

## Hint

In 2007, a Gallup poll estimated that 45% of U.S. adults rated their financial situation as “good.” Is the proportion different for this year? Which of the following samples could be used to test the null hypothesis p = 0.45? Mark each as valid (OK to use to test the hypothesis) or not valid (should not be used to test the hypothesis).

http://phhp-faculty-cantrell.sites.medinfo.ufl.edu/files/2013/10/LBD_12021_prop2.swf

## Hint

We plan to poll 200 students enrolled in statistics at your college by distributing surveys during class. Which of the following hypotheses could be tested with the survey results? Mark each as valid (OK to use to test the hypothesis) or not valid (should not be used to test the hypothesis.)

http://phhp-faculty-cantrell.sites.medinfo.ufl.edu/files/2013/10/LBD_12022_prop2.swf

## Hint

This document is linked from Proportions (Step 2).