An important quality characteristic of water is the

Chapter 6, Problem 40E

(choose chapter or problem)

QUESTION:

An important quality characteristic of water is the concentration of suspended solid material. Following are 60 measurements on suspended solids from a certain lake. Construct a stem-and-leaf diagram for these data and comment on any important features that you notice. Compute the sample mean, the sample standard deviation, and the sample median. What is

the 90th percentile of concentration?

42.4 65.7 29.8 58.7 52.1 55.8 57.0 68.7 67.3 67.3

54.3 54.0 73.1 81.3 59.9 56.9 62.2 69.9 66.9 59.0

56.3 43.3 57.4 45.3 80.1 49.7 42.8 42.4 59.6 65.8

61.4 64.0 64.2 72.6 72.5 46.1 53.1 56.1 67.2 70.7

42.6 77.4 54.7 57.1 77.3 39.3 76.4 59.3 51.1 73.8

61.4 73.1 77.3 48.5 89.8 50.7 52.0 59.6 66.1 31.6

Questions & Answers

QUESTION:

the 90th percentile of concentration?

42.4 65.7 29.8 58.7 52.1 55.8 57.0 68.7 67.3 67.3

54.3 54.0 73.1 81.3 59.9 56.9 62.2 69.9 66.9 59.0

56.3 43.3 57.4 45.3 80.1 49.7 42.8 42.4 59.6 65.8

61.4 64.0 64.2 72.6 72.5 46.1 53.1 56.1 67.2 70.7

42.6 77.4 54.7 57.1 77.3 39.3 76.4 59.3 51.1 73.8

61.4 73.1 77.3 48.5 89.8 50.7 52.0 59.6 66.1 31.6

ANSWER:

Step 1 of 3

A stem-and-leaf diagram is a good way to obtain an informative visual display of a data set where each number consists of at least two digits. To construct a stem-and leaf diagram, use the following steps.

Divide each number into two parts: a stem, consisting of one or more of the leading digits, and a leaf, consisting of the remaining digit. List the stem values in a vertical column. Record the leaf for each observation beside its stem. Write the units for stems and leaves on the display.