Question

The candy company that makes M&M’s claims it produces 10% green M&M’s . Assuming that Bulk Barn’s stock of M&M’s provides a good representation of the true color distribution of all M&M’s, we go to Bulk Barn and take a simple random sample of 50 M&M’s to estimate the proportion of green M&M’s. In our sample, we end up with 7 green M&M’s.

Compute the critical value (rounded to one decimal point) we will need to construct a 93% confidence interval for the proportion of green M&M’s produced. Assume such an interval is valid.

Correct answer is 1.8

Answer 1

we know that for 93% confidence interval critical value will fall between ((1-0.93)/2)*100

and (1-(1-0.93)/2)*100 percentile or between 3.5 and 96.5 percentile

from normal value table for 96.5th percentile ; critical z =1.81 ~ 1.8

( please revert if you require any help in finding the value from table/calculator)