Answer:
395, 17.212
(360.576,429.424)
Step-by-step explanation:
Given that a procedure yields a binomial distribution with n trials and the probability of success for one trial is p.
Here [tex]n=1580and p =1/4 =0.25\\q = 0.75\\np = 395 and\\nq = 1185[/tex]
Since np and nq are greater than 5 by rule of thumb we can approximate binomial to normal.
Mean = np = 395
Variance = npq = [tex]395*0.75=296.25[/tex]
Std dev = 17.212
Thus X no of successes is N(395, 17.212)
THe the minimum usual value mu minus 2 sigma and the maximum usual value mu plus 2 sigma would be
[tex]395-2(17.212), 395+2(17.212)\\= 360.576,429.424[/tex]