Question

A sample of 15 passenger cars was

tracked for a month and the a

average gas

mileage was noted.

The numbers are

29 30 25 36

33 21 33

40 31 19 16

32 23 32 34

a) Make a histogram

of the data.

b) Make a stem and leaf plot.

c) Discuss modality and symmetry.

Identify gaps and suspected

outliers if any

exist.

d) Find the mean and

standard deviation.

e) Find the median and IQR.

f) Which summary statistics

would you report as measures of

center and spread?

Why?

Answer 1

a) Make a histogram of the data.

The histogram is:

b) Make a stem and leaf plot.

The stem and leaf plot is:

Frequency	Stem	Leaf
2	1	6 9
2	2	1 3
2	2	5 9
7	3	0 1 2 2 3 3 4
1	3	6
1	4	0
15

c) Discuss modality and symmetry. Identify gaps and suspected outliers if any exist.

The distribution is skewed and there are no outliers in the data.

d) Find the mean and standard deviation.

mean	28.93
sample standard deviation	6.73

e) Find the median and IQR.

1st quartile	24.00
median	31.00
3rd quartile	33.00
interquartile range	9.00

f) Which summary statistics would you report as measures of center and spread? Why?

Mean and standard deviation because there are no outliers in the data.