Many birds are injured or killed by flying into windows. It appears that birds d

Question

Many birds are injured or killed by flying into windows. It appears that birds don't see windows. Can tilting windows down so that they reflect earth rather than sky reduce bird strikes? Place six windows a the edge of a woods: two vertical, two tilted 20 degrees, and two tilted 40 degrees. During the next four months, there were 53 bird strikes, 31 on the vertical windows, 14 on the 20-degree windows, and 8 on the 40-degree windows. If the tilt has no effect, we expect strikes on windows with all three tilts to have equal probability. Test this null hypothesis. What do you conclude?

There is very strong evidence (P<0.01) that tilting windows changes the probability of bird strikes.

There is evidence (P=0.04) that tilting windows changes the probability of bird strikes.

There is marginal evidence (P=0.07) that tilting windows changes the probability of bird strikes.

There is no evidence (P=0.32) that tilting windows changes the probability of bird strikes.

Explanation / Answer

H0: The strikes on windows with all three tilts to have equal probability

H1: The strikes on windows with all three tilts to have not equal probability

From the given data

Test Statistic, X^2: 16.1132
Critical X^2: 5.991471
P-Value: 0.0003

correct Answer: Option (A) There is very strong evidence (P<0.01) that tilting windows changes the probability of bird strikes.

Observed Probability Expected freq (Oi) freq (Ei) (Oi-Ei)^2/Ei Vertical Window 31 0.33333333 17.66667 10.06289308 20 degree 14 0.33333333 17.66667 0.761006289 40-degree 8 0.33333333 17.66667 5.289308176 53 16.11320755

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