stats & z-scores: estimating percentage entering college

reachyourgoals

New member
Joined
Feb 19, 2009
Messages
1
During the 90's about 63% of high school graduates enrolled in college. The pollsters hope to estimate the percentage of this year's seniors planning to attend college with a margin of error no greater than 4%. What size sample would suffice if they want to have 90% confidence in the estimate?

Margin of error = z score ?(pq/n)
0.04= z score ?(0.63*0.37 /n)
90 percent confidence
Invnorm(.05)= -1.645
0.04= -1.645 ?(0.2331/n)

N= 394

Am i finding the z-score correctly?
Is the rest of my math correct?
Thsi is supposed to be an essay. Should i be checking for conditions? which ones?
 
Re: Please Give Speedy Help- statistics involving z-score

That looks fine, except round up to 395
 
Top