Data 205 Lab Assignment:

Unit 8 Correlation Lab

Exercise 2: Cross-Tabs (4 points)

We can use contingency tables to figure out which students may have dropped the class. We will use the

## ## ## Cell Contents ## |-------------------------| ## | N | ## | N / Col Total | ## |-------------------------| ## ## ## Total Observations in Table: 107 ## ## ## | data$nolab ## data$notest | credit for lab | no credit for lab | Row Total | ## -------------------|-------------------|-------------------|-------------------| ## credit for test | 68 | 1 | 69 | ## | 0.800 | 0.045 | | ## -------------------|-------------------|-------------------|-------------------| ## no credit for test | 17 | 21 | 38 | ## | 0.200 | 0.955 | | ## -------------------|-------------------|-------------------|-------------------| ## Column Total | 85 | 22 | 107 | ## | 0.794 | 0.206 | | ## -------------------|-------------------|-------------------|-------------------| ## ## ## Statistics for All Table Factors ## ## ## Pearson's Chi-squared test ## ------------------------------------------------------------ ## Chi^2 = 43.44737 d.f. = 1 p = 4.355162e-11 ## ## Pearson's Chi-squared test with Yates' continuity correction ## ------------------------------------------------------------ ## Chi^2 = 40.2151 d.f. = 1 p = 2.27483e-10 ## ##

1. Looking at the contingency table, which variable is set up as the dependent and which is set up as the independent variable?

2. What is the association between getting credit for the lab and getting credit for the test in terms of sign, size, and significance (use the first Chi-squared test to determine significance)?