Question 75493
Q1. if Z is a standard normal variable, find the probability. P(-0.73
Comment: Something must be missing in this posting.
-------------------------
 Q2. express the confidence interval in the form of +/-E, -0.052 
Comment: Something is missing here.
--------------
Q3. find the critical value Z(alpha/2) that corresponds to a degree of confidence of 91%
Half of 91% is 45.5%
The z-score that corresponds to 4.5% and to 95.5% is -1.6954 and +1.6954
-------------
 
Q4. find the minimum sample size you should use to assure that your estimate of P will be within the required margin of error around the population P. Margin of error:0.04 confidence level:94% P and q unknown.
E=z*sqrt(pq/n)
sqrt(n)=[z*sqrt(pq)]/E
sqrt(n) = [1.88079 sqrt(.5*.5)]/0.04
sqrt(n) = [0.9403968049]/0.04
sqrt(n) = 23.5099
Square both sides to get:
n=552 (rounded down to the whole number)
============
Cheers,
Stan H.