
Normal Distribution
Would really appreciate if someone could help !!!
1) If a large number of samples of size n are taken from B(20,0.2) and approximately 90% of the sample means are less than 4.354, estimate n.
2) i. The random variable has the distribution . Given that and are to independent observations of , find
ii. The random variable is related to by the formula , where and are constants with . Given that , find the values of and , and hence find the values of a and b.
thanks!!

1) If X is the corresponding random variable, then
=>
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Find the inverse cdf of a standard normal distribution having cumulative probability ; that will be equal to . Then solve for .
2)i) HINT: You have to find where
ii) HINT: The distribution of Y is symmetric about . So the mean of is . For variance, replace by and proceed.

for 1), i did as you taught me to, but the answer given for n is 42 whereas i got 0.00134182 oO
and as for the rest, i got them! thanks!!

Horrible mistake! I read it normal instead of binomial! The LHS will be
