# Question: From Example 7 trading volumes for General Electric stock on

From Example 7, trading volumes for General Electric stock on Mondays and Fridays during

February through April of 2011 were given as follows

The Monday data have x = 51.82, s = 17.19, Q1 = 43, Median = 45, Q3 = 64.

The Friday data have x = 50, s = 11.34, Q1 = 41.5, Median = 47, Q3 = 54.5.

a. Construct a histogram or box plot of the Friday data. What assumptions are needed to construct a 95% confidence interval for μ? Point out any assumptions that seem questionable.

b. Using the Friday data and appropriate given summary statistics, show that the 95% confidence interval is (42.795, 57.205). Interpret it in context.

c. Check whether this data set has any potential outliers according to the criterion of (i) 1.5 * IQR below Q1 or above Q3 and (ii) 3 standard deviations from the mean.

d. The value 80 is quite a bit larger than the others. Delete this observation, find the new mean and standard deviation, and use software to construct the 95% confidence interval for μ. How does it compare to the 95% confidence interval (42.796, 57.204) using all the data?

February through April of 2011 were given as follows

The Monday data have x = 51.82, s = 17.19, Q1 = 43, Median = 45, Q3 = 64.

The Friday data have x = 50, s = 11.34, Q1 = 41.5, Median = 47, Q3 = 54.5.

a. Construct a histogram or box plot of the Friday data. What assumptions are needed to construct a 95% confidence interval for μ? Point out any assumptions that seem questionable.

b. Using the Friday data and appropriate given summary statistics, show that the 95% confidence interval is (42.795, 57.205). Interpret it in context.

c. Check whether this data set has any potential outliers according to the criterion of (i) 1.5 * IQR below Q1 or above Q3 and (ii) 3 standard deviations from the mean.

d. The value 80 is quite a bit larger than the others. Delete this observation, find the new mean and standard deviation, and use software to construct the 95% confidence interval for μ. How does it compare to the 95% confidence interval (42.796, 57.204) using all the data?

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