SOLUTION: Find the margin of error E that corresponds to the given statistics and confidence level: a) n = 1000, x = 400, 95% confidence b) n = 500, x = 220, 99% confidence c) 98% confide

Algebra ->  Probability-and-statistics -> SOLUTION: Find the margin of error E that corresponds to the given statistics and confidence level: a) n = 1000, x = 400, 95% confidence b) n = 500, x = 220, 99% confidence c) 98% confide      Log On


   



Question 1171537: Find the margin of error E that corresponds to the given statistics and confidence level:
a) n = 1000, x = 400, 95% confidence
b) n = 500, x = 220, 99% confidence
c) 98% confidence; the sample size is 1230, of which 40% are successes.
d) 20. 90% confidence; the sample size is 1780, of which 35% are successes.

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
the CI is mean+/- margin of error, and the latter is z*sqrt(p*(1-p)/n)
so for a it is 1.96*sqrt(0.4*0.6/1000)=0.030
-
b.this is 2.576*sqrt(.44*.56/500)=0.0572
-
c. This is 2.326*sqrt(.4*.6/1230)=0.0325
-
d. This is done for 90% confidence; not clear what the "20" means.
E=1.645*sqrt(.35*.65/1780)=0.0186