Posted by Andrea on Wednesday, January 28, 2009 at 8:08pm.
I saw that this was already answered but I can't find it if anyone knows, can you point me in the right direction?
A recent poll of 700 people who work indoors found that 278 of them smoke.If the researchers want to be 98% confident of thier results to within 3.5%, how large a sample is necessary?

College Statistics 2  MathGuru, Wednesday, January 28, 2009 at 10:17pm
Here's one formula you can use for a problem of this type:
n = [(zvalue)^2 * p * q]/E^2
Note: n = sample size needed; ^2 = squared; .4 for p and .6 for q (q = 1  p). E = maximum error, which is .035 (3.5%) in the problem. Zvalue is found using a ztable (find the value that corresponds to 98% confidence). Substitute into the formula. Round your answer to the next highest whole number.
Note: 278/700 is approximately .4 in decimal form.
I hope this will help.

Elementary Statistics  Roxanne Singleton, Monday, November 2, 2009 at 9:46am
2. A research team studied the ages of patients who had heart attacks caused by smoking. The ages of 34 patients who suffered a heart attack were as follows.
29 30 36 41 45 50 57 61 28 50 66 58
60 38 36 47 40 32 58 46 61 40 55 32
61 56 45 46 62 66 38 40 40 27
Construct a StemandLeaf Plot using this data with Key: 5  7 = 57.
Answer This Question
Related Questions
 statistics  a recent poll of 700 peole who work indoors found that 278 of the ...
 maths  number of films seen by a group of people during the past year No of ...
 collison problem in physics  I saw this problem half answered already but the ...
 statistics  in 1995,the gallup poll asked a sample of 620 adults whether their ...
 statistics  An online site presented this question, 'Would the recent norovirus...
 Statistics  A poll of 92 students found that 48% were in favor of raising ...
 statistics  An online site presented this question, 'Would the recent norovirus...
 statistics  An employer polled its employers to see if they agree with the ...
 statistics  A poll of 700 persons attending the Taste of Chicago showed that ...
 Statistics  A recent Gallup Poll dealt with the proportion of Canadians who ...
More Related Questions