Chapter 4, Problem 31E

(a)

To determine

To construct: the stem and leaf plot on the basis of given data

Explanation of Solution

Given:

2.22, 2.27, 2.26, 2.36, 2.21, 2.28, 2.46, 2.38, 2.45, 2.27, 2.29, 2.33, 2.24, 2.23, 2.32, 2.27

Graph:

Stem unit = 0.1

Leaf unit = 0.001

  

By seeing the stem plot, it is observed that the distribution appears not symmetric. It is skewed to right and unimodal. There is an outlier and only few stations have higher prices.

(b)

To determine

To Explain: the shape, centre and spread of this distribution.

Explanation of Solution

The shape is skewed to the right since there are more numbers on the left than on the right. The centre is $2.275 if there are using the median as the measure of centre (here, the median is average of the 8^th and 9^th numbers, which are $2.27 and $2.28. respectively). The spread is $0.25 if there are using the range as the measure of spread (here the range is $2.46-$2.21=$0.25).

(c)

To determine

To find: the unusual feature.

Explanation of Solution

One outlier in the distribution which displays that the prices of two gas stations are higher than prices of other gas stations. Between two gas stations there is a gap.