M7 discusion Assignment Example | Topics and Well Written Essays - 500 words

M7 discusion - Assignment Example The row totals and the column totals in a two-way table give the marginal distributions of the two variables separately. There are two marginal distributions in a two-way table and each marginal distribution from a two-way table is a distribution for a single categorical variable. The conditional distribution of the row variable for one specific value of the column variable is each entry in the column as a percent of the column total. The conditional distribution of the column variable for one specific value of the row variable is each entry in the row as a percent of the row total. The complete conditional distribution gives the proportions or percents for all possible values of the conditioning variable. The conditional distribution reveals the nature of association between two categorical variables. The chi-square statistic (denoted by χ2) measures the relative difference between expected and observed frequencies (cell counts). It is a measure of how much the observed cell counts in a two-way table diverge from the expected cell counts. The Chi-square statistic is computed by first taking the difference between each observed count and its corresponding expected count, and Taking Square of these values, than dividing each squared difference by the expected count, and finally taking sum of all the values. The chi-square is appropriate to use when the variables are simple random samples (SRSs), measured on categorical level and the average expected cell count is 5 or greater and all individual expected counts are 1 or greater, except in the case of 2 Ãâ€" 2 tables. All four expected counts in a 2 Ãâ€" 2 table should be 5 or greater. The two models for using a chi square test are ‘Comparing several populations: the first model’ and ‘Test independence: the second model’. In the first model, independent SRSs are drawn