How accurate are pollsters in predicting the outcomes of congressional elections? The table shows the actual number of Democratic party seats in the House of Representatives and the number predicted by the Gallup organization for nonpresidential election years between World War II and 1998.
a) Is there a significant difference between the number of seats predicted for the Democrats and the number they actually held? Test an appropriate hypothesis and state your conclusions.
| Democratic Party Congressmen |
| Year |
Predicted |
Actual |
| 1946 |
190 |
188 |
| 1950 |
235 |
234 |
| 1954 |
232 |
232 |
| 1958 |
272 |
283 |
| 1962 |
259 |
258 |
| 1966 |
247 |
248 |
| 1970 |
260 |
255 |
| 1974 |
292 |
291 |
| 1978 |
277 |
277 |
| 1982 |
275 |
269 |
| 1986 |
264 |
258 |
| 1990 |
260 |
267 |
| 1994 |
201 |
204 |
| 1998 |
211 |
211 |
b) Is there a strong association between the pollsters predictions and the outcomes of the elections? Test an appropriate hypothesis and state your conclusions.