Question

Jim is a taxi driver who keeps track of his meter readings. The results for the past twenty meter readings (rounded to the nearest dollar) are given below: 15, 46, 7,5, 9, 24, 21, 37, 19, 51, 17, 49, 8, 57, 35, 42, 22, 12, 33, 16 Make a stemplot of the data and briefly describe its center, shape, and spread.

Answer 1

The stemplot is a type of frequency data that is presented in table form. It is like a histogram, but you don't use bars. Instead, you make a table where the left side represent the stem, while the right side represent the leaves. 

First, arrange the data set from lowest to largest. Then, sort the numbers based on their tens digit. All the common tens digit should be placed on the stem side. The corresponding ones digit are placed in the leaves side, in which they are placed side by side. Fro example, for the data group: 12, 15, 17 ,19. The left side would be 1, then the right side are numbers containing 2, 5, 7 and 9, The stemplot is shown in the attached picture.

To determine the center, just literally find the central data by counting from both ends of the stemplot, until you reach the center. That would be 22, as encircle in the picture. Next, the spread is the topmost number to the bottom. Thus, the range is from 5 to 57. Lastly, the shape of the stemplot is determined by looking at the length of the leaves. The top leaves only contain number, while the bottom leaves contain 2 or 3 numbers. Thus, the spread is bottom-skewed, or more distributed in the bottom area.