homework help

A researcher wants to determine p, the proportion of all blue back crabs that are left-handed.Assume that an estimate of phatfound from a previous study is 10%. How many crabs must be sampled so that the sample proportion has a margin of error of 0.05 with 90% confidence?

a.138

b.35

c.36

d.139

Question 2

Use the Standard Normal distribution table (Table A-2) to find the critical value (z alpha/2)that corresponds a confidence level of 50%.

a.0.675

b.0.7734

c.0.315

d.0.5987