Comparisons of Variability of Sample Statistics among Differently Sized Samples

The graphs below summarize the data you collected as homework when using Data Desk to select samples of various sizes from the San Diego Voter data base. Each graph shows a plot of statistics calculated from 5 samples of 300 voters, 5 samples of 500 voters, 5 samples of 1500 voters, and 5 samples of 3000 voters, each sample being taken independently of the others.

Variability of Party Affiliation Percentages for Differently-Sized Samples

Percent of Democrats in Sample versus Sample Size

Percent of Independents in Sample versus Sample Size

Percent of Libertarians in Sample versus Sample Size

Percent of Others in Sample versus Sample Size

Percent of Republicans in Sample versus Sample Size

Variability of Ethnic Group Percentages for Differently-Sized Samples

Percent of Group 0 in Sample versus Sample Size

Percent of Group 1 in Sample versus Sample Size

Percent of Group 2 in Sample versus Sample Size

Percent of Group 3 in Sample versus Sample Size

Percent of Group 4 in Sample versus Sample Size

Percent of Group 5 in Sample versus Sample Size

Variability of Income Statistics for Differently-Sized Samples

Sample Mean Democrat Income versus Sample Size

Sample StandDev Democrat Income versus Sample Size

Sample Mean Independent Income versus Sample Size

Sample StandDev Independent Income versus Sample Size

Sample Mean Libertarian Income versus Sample Size

Sample StandDev Libertarian Income versus Sample Size

Sample Mean Other Income versus Sample Size

Sample StandDev Other Income versus Sample Size

Sample Mean Republican Income versus Sample Size

Sample StandDev Republican Income versus Sample Size