Posted by sammy on Saturday, June 21, 2008 at 5:26pm.
a recent poll of 700 peole who work indoors found that 278 of the smoke. If the researchers want to be 98% confident of thier results to within 3.5% how large a sample is necessary?
how do i work this problem?

statistics  MathGuru, Saturday, June 21, 2008 at 7:47pm
Try this formula:
n = [(zvalue)^2 * p * q]/E^2
= [(2.33)^2 * .397 * .603]/.035^2
I'll let you finish the calculation.
Note: n = sample size needed; .397 (which is approximately 278/700 in decimal form) for p and .603 (which is 1  p) for q. E = maximum error, which is .035 (3.5%) in the problem. Zvalue is found using a ztable (for 98%, the value is approximately 2.33). Symbols: * means to multiply and ^2 means squared.
I hope this will help.
Answer This Question
Related Questions
 College Statistics 2  I saw that this was already answered but I can't find it ...
 statistics  I need a estimate within $25, the true average of amount of postage...
 statistics  The Academy of Orthopedic Surgeons states that 80% of women wear ...
 Stat Help  A researcher wishes to be 95% confident that her estimate of the ...
 Statistic  birth weight of infants: a health care professional wishes to ...
 Statistic  birth weight of infants: a health care professional wishes to ...
 Statistics  The Academy of Orthopedic Surgeons states that 80% of women wear ...
 statistics  A researcher is interested in estimating the noise levels in ...
 Math/statistics  a recent study indicated that 29% of the 100 women over age 55...
 Statistics  You are getting ready to take a sample from a large population, and...
More Related Questions