Question

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.t These data are also available for download at the Companion Sites for this text. For convenience, the data are presented in increasing order. 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 7.27.2 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 8.18.1 8.2 8.2 8.2 8.2 8.2 8.2 82 8.4 8.5 86 8.7 8.8 8.8 Is the glven data nominal, ordinal, interval, or ratio? O nominal O ordinal O interval ratio Explain. O The data can be arranged in order, differences between values have a meaning, but there is not a true zero that has meaning beyond a place on the scale. O The data cannot be arranged in order O The data can be arranged in order but differences between values do not have a meaning. O The data can be arranged in order, differences between values have a meaning, and there is a true zero that has meaning beyond a place on the scale Write a brief description in which you outline how you would obtain a random sample of 102 West Texas water wells. Explain how random numbers would be used In the selection process O One could assign consecutive numbers to each well in West Texas and then use a random number table or a computer package to draw the simple random sample. 。One could assign consecutive numbers to each well in Texas and then use a random number table or a computer package to (hw the simple random sample. O One could assign consecutive numbers to each well in several neighborhoods of Texas and then use a random number table or a computer package to draw the simple random sample. O One could assign consecutive numbers to each well in the most rural areas of West Texas and then use a random number table or a computer package to draw the simple random sample. O One could assign consecutive numbers to each well in one neighborhood of West Texas and then use a random number table or a computer package to draw the simple random sample. Look at a stem-and-leaf plot of the data. Use five lines per stem so that leaf values 0 and 1 are on one line, 2 and 3 are on the next line, 4 and 5 are on the next, 6 and 7 are on the next, and 8 and 9 are on the last line of the stem. Are there any unusually high or low pH levels in this sample of wells? There is a large gap beside some outliers on the left side of the plot. There are unusually low pH levels n the sample. O There is a large gap beside some outliers on the right side of the plot. There are unusually high pH levels in the sample. There are no large gaps on either side of the plot, indicating that there are no outlers. There are no unusualy high or low pH levels n the sample gap beside some outliers on the both sides of the plot. There are unusually high and low pH levels In the sample. How many wells are neutral (pH of 7) wells Look at a histogram of the data using five classes. Is the pH distribution for these wells symmetric or skewed? O symmetric O skewed right skewed left Are lower or higher values more common? O lower values are more common O higher values are more common O lower and higher values are equally common

Answer 1

A) The given data is in interval scale.

C) Interval is correct

b) The data can be arranged in order, the difference has a meaning but there is not a true zero of pH.

Hence, A) is correct.

c) To obtain random samples, A) is correct where we assign consecutive numbers to each well in West Texas and then use a random number table.

d) 8 wells are neutral

e) The stem and leaf plot is not shown but there are some outliers on right side of the plot. Unusual high pH values like 8.7, 8.8 etc.B is correct.

f) The histogram is skewed right as most of the values have low pH which can be observed from the data.

B) skewed right is correct

g) lower values are more common. A) is correct