Problems on statistics and probability are presented. The answers to these problems are at the bottom of the page.

1. Given the data set

4 , 10 , 7 , 7 , 6 , 9 , 3 , 8 , 9

Find

a) the mode,

b) the median,

c) the mean,

d) the sample standard deviation.

e) If we replace the data value 6 in the data set above by 24, will the standard deviation increase, decrease or stay the same?

2. Find x and y so that the ordered data set has a mean of 42 and a median of 35.

17 , 22 , 26 , 29 , 34 , x , 42 , 67 , 70 , y

3. Given the data set

62 , 65 , 68 , 70 , 72 , 74 , 76 , 78 , 80 , 82 , 96 , 101,

find

a) the median,

b) the first quartile,

c) the third quartile,

c) the interquartile range (IQR).

4. The exam grades of 7 students are given below.

70 , 66 , 72 , 96 , 46 , 90 , 50

Find

a) the mean

b) the sample standard deviation

5. Twenty four people had a blood test and the results are shown below.

A , B , B , AB , AB , B , O , O , AB , O , B , A

AB , A , O , O , AB , B , O , A , AB , O , B , A

a) Construct a frequency distribution for the data.

b) If a person is selected randomly from the group of twenty four people, what is the probability that his/her blood type is not O?