For a study of free-living populations of the fruitfly Drosophila subobscura, researchers placed baited traps in two woodland sites and one open-ground area. The numbers of male and female flies trapped in a single day are given in the table.

Here is computer output for a chi-square test to compare the sex ratios at the three sites.
X-squared = 49.7, df = 2, p-value = 1.58e-11
(a) State the null and alternative hypotheses in context.
(b) Compute the expected frequencies.
(c) If α = 0.05, what is your conclusion regarding H0?
(d) Construct a table that displays the data in a more readable format, such as the one in Exercise 10.5.1.

Transcribed Image Text:

Woodland Woodland Open site I site II ground Males Females Total 74 136 210 120