A grocery store sells apples in bags that are claimed to have a mean weight of 3 lbs. The Department of Weights and Measures tests 100 randomly selected bags and finds a mean weight of 2.8 lbs.

Answer 1

sample size = n = 100

CI = mean +/-zs/sqrn

=2.8 +/-2s/sqr100 where z = 2 for a 95% CI=Confidence Interval

MOE=Margin Of Error = 2s/10 = s/5 = 20% of the sample standard deviation

for 3 lbs to be within the MOE, the sample standard deviation must be greater than 1 lb

that seems unlikely. their scales can't be that far off, with bags varying from 2 to 4 lbs?