Question

An online pet food company wants to investigate if cat or dog owners are more likely to re-order pet food. They randomly select 150 subscribers, of whom 95 are cat owners and 55 are dog owners. Of the cat owners, 65 regularly re-order; of the dog owners, 25 regularly re-. Which of the following is closest to the expected number of cat owners who re-order?

20

30

40

50

60

Answer 1

solution:

first of all prepare the contingency table

	Cat owner	Dog owner	Total
Re-order	65	25	90
not reorder	30	30	60
Total	95	55	150

the above table represents the observed data

we have to find the expected number of cat owner who regularly reorder

so, expected number = (row total * column total) / total number

total of row of reorder = 90

total of column of cat owner = 95

so required expected number = (90 * 95) / 150 = 57

which is close to 60 in the given option ,

so answer is 60