Question 1 There are 7 terms in a series are 1 3 5 7 9 11 13. What' the difference between the mean and median?

-- Answer -- 7

Mean = (1 + 3 + 5 + 7 + 9 + 11 + 13) / 7 = 7

Median = 7 (the middle number)

Question 2 10 kids went to school and during the year, 1 kid went 230 days, 3 kids went 232 days 1 kid went 235 days, 2 kids went 236 days, and 3 kids went 240 days. What's the median?

-- Answer -- 235.5

Write down the group of numbers: 230, 232, 232, 235, 235, 236, 236, 240, 240, 240

Put the group of numbers in order: same as above

Choose the middle number: Since there are an even number of number, the average of the middle 2 numbers is used, (235+236)/2 = 235.5

Question 3 Which 10 digit interval must contain the median test score (see figure below)?

-- Answer -- 71–80

There are 30 test scores (see 41–100 bar on the right). The median would be the average of the 15th & 16th test scores.

41–50 = 2, 51–60 = 3, 61–70 = 5, 71–80 = 8, 81–90 = 6, 91–100 = 6

The 15th & 16th test scores lies in the range, 71–80.