Six months ago (subscription 1), a survey was undertaken to determine the degree of support for a national party leader. Of a sample of 1,100, 56% indicated they would vote for this politician. This month (subscription 2), another survey of 800 voters revealed that 46% now support the leader.
a. At the 5% significance level, can we infer that the national leader's popularity has decreased?
b. Estimate with 95% confidence the decrease in percentage support between now and 6 months ago.
What are the hypotheses?