Homework 7
This is a medium homework, counting twice as much as a small homework.
Due October 24, 2013 as a hard copy (typed) at beginning of class.
Name:_____________________________________
Questions about Section A of Chapter: (TAN.3) When stocasticity does and doesn't matter
(1) In one thoughtful paragraph, describe how Cornell researchers measured the effect of beef television advertisements on beef demand. This is in section A.3.
(2) Describe the difference between a sample average and a population average (described in section A.2) in the context of the experiment in section A.3. That is, what is the difference between what the researchers can measure and what they wish to measure? (One or two sentences)
(3) In section A.3, which group expressed a higher average value for beef (ignoring stochasticity): the group who watched the commercial or the group who did not? (Tell me the exact average values for each group in one or two sentences, without worrying about whether they are statistically different.)
(4) In the Cornell experiment, if we allow for the role of stochasticity, did beef advertisements increase the value of beef to consumers? Explain, describing the p-value and what it means. (Note: This is where you talk about the hypothesis test results. Three or more sentences are necessary.)
A hypothetical experiment
In class we wanted to test the effectiveness of the two television commercials below, where we estimated the value consumers place on two half-pound pork chops after watching one of the two commercials. We pretended like we gathered the data ourselves for analysis. The data are available in this Google spreadsheet.
Commercial A
Commercial B
(5) Using these data, ...
the average value / bid after watching commercial A was ________
and consisted of _________ observations. The average value / bid after
watching commercial B was ________ and
consisted of
_________ observations.
(6) If the sample sizes were really, really large and we did not need to worry about the results being influenced by stochasticity, what do the average values / bids in question 5 imply about the relative effectiveness of the two commercials?
(7) Using these data, use the T.TEST function in Excel to determine if one bid is statistically different than another. Report the p-value, describe how you interpret the p-value, and what it means for a company wishing to know the relative effectiveness of the two commercials.
