Discussion:
Q1) Assume that the population proportions are to be estimated from the samples described. Find the margin of error and the 95% confidence interval.
Sample size = 256, sample proportion = 0.6
Q2) Importance: A Phone survey of 500 people revealed that 99% of those surveyed ranked good relationships as important or very important, 98% ranked financial security as important or very important. Third on the list was religious fulfillment at 86%, followed by a good sex life at 82%, and job satisfaction at 79%. The margin of error for the study was reported at 4% points.
Is the reported margin of error consistent with the sample size?
Q3) For each of the following, give the 95% confidence interval:
a) 17.2% of people in Florida are inactive, sample size = 1,500.
b) 13.2% of people in California have poor diets, sample size = 2,500.
c) 22.9% of people in Hawaii eat pineapple regularly, sample size = 3,500
Q4) A random selection of 1,600 people found that 900 support a certain lawyer in a political race. Based on the sample, would you claim that the lawyer will win a majority of the votes?
Q5) Estimate the minimum sample size needed to achieve the following margins of error:
E = 0.02, E = 0.05, E = 0.04, E = 0.035
Q6) Margin of error: In general, if one wished to decrease the margin or error by a factor of 2 in an estimation of a population proportion from E = 0.02 to 0.01, by what factor should the sample size be increased?