Determine the sample size n needed to construct a 90​%

Determine the sample size n needed to construct a 90​% confidence interval to estimate the population proportion when p=0.68 and the margin of error equals 8​%.
n=nothing ​(Round up to the nearest​ integer.)Determine the margin of error for an 80​% confidence interval to estimate the population mean with σ=49 for the following sample sizes.
​a)
n
=
38
​b)
n
=
45
​c)
n
=
69
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​a) When n=38​, the margin of error for an 80​% confidence interval is nothing.
​(Round to two decimal places as​ needed.)
​b) When n=45​, the margin of error for an 80​% confidence interval is nothing.
​(Round to two decimal places as​ needed.)
​c) When n=69​, the margin of error for an 80​% confidence interval is nothing.
​(Round to two decimal places as​ needed.)Determine the margin of error for an 80​% confidence interval to estimate the population mean when s​ = 37 for the sample sizes below.
​a)
n=10
​b)
n=33
​c)
n=52
​a) The margin of error for an 80​% confidence interval when n=10 is nothing.
​(Round to two decimal places as​ needed.)
​b) The margin of error for an 80​% confidence interval when n=33 is nothing.
​(Round to two decimal places as​ needed.)
​c) The margin of error for an 80​% confidence interval when n=52 is nothing.
​(Round to two decimal places as​ needed.)Construct a 95​% confidence interval to estimate the population mean when x=51 and s​ = 12.5 for the sample sizes below.
​a)
n=24
​b)
n=40
​c)
n=55
​a) The 95​% confidence interval for the population mean when n=24 is from a lower limit of nothing to an upper limit of nothing.
​(Round to two decimal places as​ needed.)
​b) The 95​% confidence interval for the population mean when n=40 is from a lower limit of nothing to an upper limit of nothing.
​(Round to two decimal places as​ needed.)
​c) The 95​% confidence interval for the population mean when n=55 is from a lower limit of nothing to an upper limit of nothing.
​(Round to two decimal places as​ needed.)