Question

Many birds are injured or killed by flying into windows. It appears that birds do not see windows. Can tilting windows down so that they reflect earth rather than sky reduce bird strikes? Researchers placed six windows at 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.

For this data, the calculated expected counts for all three window types are 17.76 , and the chi‑square statistic is 16.11. With ?-value<0.001, there is very strong evidence that the three tilts differ in proportion of accidental bird strikes.

Choose the correct interpretation of the result of the chi‑square test and conclusion about the efficacy of tilting windows.

a) The data and the chi‑square components show that fewer birds than expected strike the vertical window and more than expected strike the 20‑degree window.

b) None of the options are correct.

c) The data and the chi‑square components show that more birds than expected strike the tilted windows and that almost none strike the vertical window.

d) The data and the chi‑square components show that more birds than expected strike the vertical window and fewer than expected strike the 40‑degree window.

Answer 1

option D) is correct

since 31 > 17.66 fr vertical

and 8 < 17.66 for 40-degree windows

d) The data and the chi‑square components show that more birds than expected strike the vertical window and fewer than expected strike the 40‑degree window.