You are examining two data sets involving test scores, set A and set B. The score 86 appears in both data sets.

In which of the following data sets does 86 represent a higher score? Explain.

(a) The percentile rank of 86 is higher in set A than in set B.

(b) The mean is 80 in both data sets, but set A has a higher standard deviation.

Applications In west Texas, water is extremely important. The following data represent pH levels in ground water for a random sample of 102 west Texas wells. A pH less than 7 is acidic and a pH above 7 is alkaline. Scanning the data, you can see that water in this region tends to be hard (alkaline). Too high a pH means the water is unusable or needs expensive treatment to make it usable (Reference: C. E. Nichols and V. E.

Kane, Union Carbide Technical Report K/UR-1).

These data are also available for download at the Companion Sites for this text. For convenience, the data are presented in increasing order.

Chapters 1–3 CUMULATIVE REVIEW PROBLEMS x: pH of Ground Water in 102 West Texas Wells 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.1 7.1 7.1 7.1 7.1 7.1 7.1 7.1 7.1 7.1 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.4 7.4 7.4 7.4 7.4 7.4 7.4 7.4 7.4 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.7 7.7 7.7 7.7 7.7 7.7 7.8 7.8 7.8 7.8 7.8 7.9 7.9 7.9 7.9 7.9 8.0 8.1 8.1 8.1 8.1 8.1 8.1 8.1 8.2 8.2 8.2 8.2 8.2 8.2 8.2 8.4 8.5 8.6 8.7 8.8 8.8 AppendixLO1