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An experimenter wishes to test whether or not two types of fish food (a standard fish
Chapter 12, Problem AP4.30(choose chapter or problem)
An experimenter wishes to test whether or not two types of fish food (a standard fish food and a new product) work equally well at producing fish of equal weight after a two-month feeding program. The experimenter has two identical fish tanks (1 and 2) to put fish in and is considering how to assign 40 fish, each of which has a numbered tag, to the tanks. The best way to do this would be to (a) put all the odd-numbered fish in one tank, the even in the other, and give the standard food type to the odd-numbered ones. (b) obtain pairs of fish whose weights are roughly equal at the start of the experiment and randomly assign one to Tank 1 and the other to Tank 2, with the feed assigned at random to the tanks. (c) proceed as in part (b), but put the heavier of the pair into Tank 2. (d) assign the fish completely at random to the two tanks and give the standard feed to Tank 1. (e) assign the fish to the tanks using any method that the researcher wants. The placebo effect doesnt apply to fish. AP4
Questions & Answers
QUESTION:
An experimenter wishes to test whether or not two types of fish food (a standard fish food and a new product) work equally well at producing fish of equal weight after a two-month feeding program. The experimenter has two identical fish tanks (1 and 2) to put fish in and is considering how to assign 40 fish, each of which has a numbered tag, to the tanks. The best way to do this would be to (a) put all the odd-numbered fish in one tank, the even in the other, and give the standard food type to the odd-numbered ones. (b) obtain pairs of fish whose weights are roughly equal at the start of the experiment and randomly assign one to Tank 1 and the other to Tank 2, with the feed assigned at random to the tanks. (c) proceed as in part (b), but put the heavier of the pair into Tank 2. (d) assign the fish completely at random to the two tanks and give the standard feed to Tank 1. (e) assign the fish to the tanks using any method that the researcher wants. The placebo effect doesnt apply to fish. AP4
ANSWER:Step 1 of 2
(a) No random assignment, because they are assigned by even and odd and thus this is not a good method.
(b) This is the best way to do it, because it takes into account similar weights and it randomly assigns them to groups.
(c) No random assignment, thus not a good method.
(d) This is a good way to do it, because this is a random assignment, but (b) also takes into account and thus (b) is a better way.
(e) Not as good as (b), because weight is a better indicator than length (for eating habits).