Zener cards are often used to test the psychic ability of in
| Zener cards are often used to test the “psychic ability” of individuals. In the Zener deck, there are five different patterns displayed, and each has a 1/5 probability of being drawn from a well-shuffled deck. The five patterns are: circle, plus sign, wavy lines, empty box, and star. One hundred trials were conducted and your very impressive friend guessed right on 41 of those trials. Given this sample, can we use the Normal approximation to the binomial? | |||||||||
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| Zener cards are often used to test the “psychic ability” of individuals. In the Zener deck, there are five different patterns displayed, and each has a 1/5 probability of being drawn from a well-shuffled deck. The five patterns are: circle, plus sign, wavy lines, empty box, and star. One hundred trials were conducted and your very impressive friend guessed right on 41 of those trials. Given this sample, can we use the Normal approximation to the binomial? | |||||||||
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Solution
A binomial approximation to a normal distribution can be made is
np > 10 and n(1-p) > 10
Here, n = 100
np = 100 * 0.2 = 20 > 10
n ( 1-p) = 100 * 0.8 = 80
variance = np(1-p) = 80 * 0.2 = 16
Hence,
the given sample can be approximated to a normal distribution
Option D is correct.
Hope this helps.
