Mileage A salesman who is on the road visiting clients thinks that, on average, he drives the same distance each day of the week. He keeps track of his mileage for several weeks and discovers that he averages 122 miles on Mondays, 203 miles on Tuesdays, 176 miles on Wednesdays, 181 miles on Thursdays, and 108 miles on Fridays. He wonders if this evidence contradicts his belief in a uniform distribution of miles across the days of the week. Explain why it is not appropriate to test his hypothesis using the chi-square goodness-of-fit test.

SE(X) measures how close the sample AVG is likely to be to the true population AVG ● What’s the problem here –SE(X) depends on population SD –we don’t know population SD ● How could you approximate the populaUse() ̂ (called “hat”) means estimate or predicted () () = √ Confidence Interval (CI): a range of values (%) that catches the average/mean of the population Margin of Error Margin of Error Interpretation of Confidence Interval: __% of all samples will