Groundwater contamination in wells. Refer to the Environmental Science&Technology (Jan. 2005) study of methyl tert-butyl ether (MTBE) contamination in New Hampshire wells, presented in Exercise. Data collected for a sample of 223 wells are saved in the MTBE file. Recall that each well was classified according to its class (public or private), aquifer (bedrock or unconsolidated), and detectable level of MTBE (below limit or detectable).
a. Consider an experiment in which the class, aquifer, and detectable MTBE level of a well are observed. List the sample points for this experiment. [Hint: One sample point is Private/Bedrock/BelowLimit.]
b. Use statistical software to find the number of the 223 wells in each sample point outcome. Then use this information to compute probabilities for the sample points.
c. Find and interpret the probability that a well has a detectable level of MTBE.
Groundwater contamination in wells. In New Hampshire, about half the counties mandate the use of reformulated gasoline. This has led to an increase in the contamination of groundwater with methyl tert -butyl ether (MTBE). Environmental Science&Technology (Jan. 2005) reported on the factors related to MTBE contamination in public and private New Hamsphire wells. Data were collected on a sample of 223 wells. These data are saved in the MTBE file. Three of the variables are qualitative in nature: well class (public or private), aquifer (bedrock or unconsolidated), and detectable level of MTBE (below limit or detect). [Note: A detectable level of MTBE occurs if the MTBE value exceeds .2 microgram per liter.] The data on 11 selected wells are shown in the accompanying table.
(11 selected observations from 223)
Well Class | Aquifer | Detect MTBE? |
Private | Bedrock | Below Limit |
Private | Bedrock | Below Limit |
Public | Unconsolidated | Detect |
Public | Unconsolidated | Below Limit |
Public | Unconsolidated | Below Limit |
Public | Unconsolidated | Below Limit |
Public | Unconsolidated | Detect |
Public | Unconsolidated | Below Limit |
Public | Unconsolidated | Below Limit |
Public | Bedrock | Detect |
Public | Bedrock | Detect |
Based on Ayotte, J. D., Argue, D. M., and McGarry, F. J. “Methyl tert -Butyl ether occurrence and related factors in public and private wells in southeast New Hampshire.” Environmental Science&Technology, Vol. 39, No. 1, Jan. 2005, pp. 9–16.
a Use graphical methods to describe each of the three qualitative variables for all 223 wells.
b. Use side-by-side bar charts to compare the proportions of contaminated wells for private and public well classes.
c. Use side-by-side bar charts to compare the proportions of contaminated wells for bedrock and unconsolidated aquifiers.
d. What inferences can be made from the bar charts of parts a–c?
We need at least 10 more requests to produce the solution.
0 / 10 have requested this problem solution
The more requests, the faster the answer.