1.From historical data, it is believed that 60% of California voters favored the death penalty. A random sample of 400 California voters was chosen and the sample proportion was calculated.

a.What is the expected value and variance of the sample proportion? What is the chance that the sample proportion is greater than 70%?

b.It was found that 300 out of 500 voters in the sample favored the death penalty. Calculate the 95% confidence interval.

Perform a test at the 0.05 level of significance to determine whether the public support for death penalty in California had been decreased. What is the p-value for the test?