Question 5 You want to test whether there is a statistically significant difference in the stock market forecasts of economists versus stockbrokers. A random sample of 36 economists and 30 stockbrokers were asked to report their forecast for the Dow Jones Industrial average for one year from today. Forecasters Number Average Forecast s (sample standard deviation) Economists 750 36 30 Stockbrokers 375 11200 10700 a. Is there a statistically significant difference between the forecasts of the economists and the stockbrokers? Perform a hypothesis test to answer this question and use a 5% significance level. Be sure to include all 4 steps of the hypothesis testing process and to interpret your result. b. Use these data to compute a 95% confidence interval for the difference in the population average forecasts for economists versus stockbrokers. Can you rule out the hypothesis that the stock market forecasts of stockbrokers and economists have the same mean by looking at this interval?

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