Question 1120532: study was conducted to see whether monetary incentives to use less water during times of drought had an effect on water usage. Sixty single family homeowners were randomly assigned to one of two groups: 1) monetary incentives and 2) no monetary incentives. At the end of three months, the total amount of water usage for each household, in gallons, was measured.
(a) What would be the appropriate hypothesis test to use to test the claim that monetary incentives reduce water usage?
i. t-test for two independent samples
ii. t-test for dependent samples
iii. z-test for population mean
iv. correlation
(b) Explain the rationale for your selection in (a). Specifically, why would this be the appropriate statistical approach?
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! These are two independent samples from a population.
Use a t-test for independent samples.
Because one is not looking at each family with monetary and non monetary incentives, a dependent sample would not be used. One does not know the parameters, so a z-test would not be used.
Correlation could be done but would not be nearly as useful.
What is bothersome is how drought is determined. If this were in a drought, then the study would answer the question. If one were thinking to measure this in normal times, then 3 months would not be enough time to know whether there was a drought.
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