Political parties want to know what groups of people support them. The General Social Survey (GSS) asked its 2014 sample, "Generally speaking, do you usually think of yourself as a Republican, Democrat, Independent, or what?" The GSS is essentially an SRS of American adults. The large two‑way table provided breaks down the responses by the highest degree the subject held. None High School Jr. College Bachelor Graduate Strong Democrat 53 198 23 81 64 Not strong Democrat 52 204
Political parties want to know what groups of people support them. The General Social Survey (GSS) asked its 2014 sample, "Generally speaking, do you usually think of yourself as a Republican, Democrat, Independent, or what?" The GSS is essentially an SRS of American adults.
The large two‑way table provided breaks down the responses by the highest degree the subject held.
| None | High School | Jr. College | Bachelor | Graduate | |
|---|---|---|---|---|---|
| Strong Democrat | 53 | 198 | 23 | 81 | 64 |
| Not strong Democrat | 52 | 204 | 31 | 70 | 49 |
| Independent, near Democrat | 40 | 163 | 26 | 66 | 42 |
| Independent | 118 | 251 | 36 | 67 | 30 |
| Independent, near Republican | 24 | 136 | 19 | 45 | 2525 |
| Not strong Republican | 19 | 142 | 30 | 71 | 30 |
| Strong Republican | 18 | 131 | 15 | 53 | 28 |
| Other party | 5 | 31 | 3 | 15 | 8 |
Use the four‑step process and the full table of counts to analyze the differences in political party support among levels of education.
The sample is so large that the differences are bound to be highly significant, but provide the chi‑square statistic and its P‑value nonetheless. The main challenge is in seeing what the data indicate.
First, we create a 2×5 table that combines counts in the three rows that mention Democrats and in the three rows that mention Republicans. We ignore the strict Independents and supporters of other parties. Then, we compare the percents of participants leaning toward each party within each education level. The table is:
| Education | ||||||
| Count (Col %) | None | High School | Jr. College | Bachelor | Graduate | Total |
| Democrat |
145 70.39 |
565 58.01 |
80 55.56 |
217 56.22 |
155 65.13 |
1,162 |
| Republican |
61 29.61 |
409 41.99 |
64 44.44 |
169 43.78 |
83 34.87 |
786 |
| Total | 206 | 974 | 144 | 386 | 238 | 1,948 |
We might think of this table as comparing all adults who lean Democrat and all adults who lean Republican.
STATE: How do conditional distributions of political leaning, given education, compare? Does the full table yield any insights not found in the compressed table?
PLAN: We will find conditional distributions for political leaning at each level of education and perform a chi‑square test on the full table, testing the null hypothesis of no relationship between educational level and political preference.
SOLVE: It is _______ to use a chi‑square test. (safe/not safe)
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