1 randomly selected people were surveyed to determine how pe

(1) randomly selected people were surveyed to determine how people rate the quality of programming

     available on television. Respondents were asked to rate the overall quality from 0 (no quality at all)

     to 100 (extremely good quality). The stem-and-leaf display of the data is shown below.

            Stem    Leaves    

                 3        24                          Stem unit = ten

                 4        03478999

                 5        0112345

                 6        12566

                 7        01

                 8

                 9        2

      Referring to the stem-and-leaf display above, what percent of the respondents rated overall television

      quality with a rating of 80 or above?

(2) Assuming an approximately normal distribution of return rates for Stock D, then an interval that  should contain approximately 95% of the monthly return rates of Stock D would be closest to which interval below? (by empirical rule)

A. (.13 , .51)         B. (.23 , .41)         C. (.04 , .59)         D. (.04 , .09)        E. (23.8 , 42.1)    

(3) The 50th percentile (or median) of Stock B

Solution

1.

: There are 25 numbers. The highest 3 are 70, 71 and 92. Only 92 is above 80. 1 out of 25 is

1/ 25 = 0.04 is the answer