Question

Both before and after a recent earthquake, surveys were conducted asking voters which of the three candidates they planned on voting for in the upcoming city council election. Has there been a change since the earthquake? Use a level of significance of 0.05. Table shows the results of the survey. Has there been a change in the distribution of voter preferences since the earthquake?

	Peter	Alan	Sui
Before	1221	1029	1694
After	2209	1735	547

What is the chi-square test-statistic for this data?
χ2=χ2=

Report all answers accurate to three decimal places.

Answer 1

H0: There has not been a change since the earthquake

H1: There has been a change since the earthquake

Let the los be alpha = 5%

The observed frequencies are

The expected frequencies are

The chi-square contribution values are

Test Statistic, X^2: 1020.8054

Degrees of freedom: 2

Critical X^2:        5.991471

P-Value:             0.0000

since Chi-square value 1020.8054 > Chi-square critical value so we reject H0

and P-value < alpha 0.05 so we reject H0

Thus we conclude that there has been a change since the earthquake