# A logistic regression model describes how the probability of voting for the Republican candidate

**QUESTION:**

A logistic regression model describes how the probability of voting for the Republican candidate in a presidential election depends on x, the voter’s total family income (in thousands of dollars) in the previous year. The prediction equation for a particular sample is

Find the estimated probability of voting for the Republican candidate when

(a) Income = +10,000,

(b) Income = +100,000. Describe how the probability seems to depend on income.

**ANSWER:**

(a)

= 0.4493 / 1.4493 = 0.31

(b)

= 2.718 / 3.718 = 0.73

The predicted probability of voting Republic can increase quite a bit as income increases.

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