The frequency distribution below shows the distribution for

The frequency distribution below shows the distribution for checkout time (in minutes) in UMUC MiniMart between 3:00 and 4:00 PM on a Friday afternoon.

Checkout Time (in minutes) Frequency Relative Frequency

1.0 - 1.9    3

2.0 - 2.9 12

3.0 - 3.9 0.20

4.0 - 4.9 3

5.0 -5.9

Total 25

2.Complete the frequency table with frequency and relative frequency. Express the relative frequency to two decimal places. (5 pts)

3. What percentage of the checkout times was at least 3 minutes? (3 pts)

4. In what class interval must the median lie? Explain your answer. (5 pts)

5. Does this distribution have positive skew or negative skew? Why? (2 pts)

Solution

2.236068 Positive Negative Has disease 160 80 240 NO disease 40 720 760 1.777778 200 800 1000 Prob Checkout Time (in minutes) Frequency Relative Frequency Atleast 3 minutes >2.9 0.4 1.0 - 1.9     3 0.12 0.36 Median 2-2.9 2.0 - 2.9 12 0.48 5.76 Mean 1