Exam 1

  1. Question

    The daily expenses of summer tourists in Vienna are analyzed. A survey with 132 tourists is conducted. This shows that the tourists spend on average 168.8 EUR. The sample variance sn-1 2 is equal to 230.6.
    Determine a 95% confidence interval for the average daily expenses (in EUR) of a tourist.

    1. What is the lower confidence bound?
    2. What is the upper confidence bound?

    Solution

    The 95% confidence interval for the average expenses μ is given by:
    [ y -1.96 sn-1 2 n ,   y +1.96 sn-1 2 n ] = [168.8-1.96 230.6 132 ,  168.8+1.96 230.6 132 ] = [166.209,171.391].


    1. The lower confidence bound is 166.209.
    2. The upper confidence bound is 171.391.