posted by lisa on .
I'm stuck on a question in MM207...
Assume you want to estimate with the proportion of students who commute less than 5 miles to work within 2%, what sample size would you need?
could someone please help me ASAP?
Try this formula:
n = [(z-value)^2 * p * q]/E^2
= [(1.96)^2 * .5 * .5]/.02^2
I'll let you finish.
Note: n = sample size needed; .5 for p and .5 for q are used if no value is stated in the problem. E = maximum error, which is .02 (2%) in the problem. Z-value is found using a z-table (for 95%, the value is 1.96).