To calculate a 99 confidence interval the value z in the mar
To calculate a 99% confidence interval, the value z* in the margin of error should equal:
2.576
1.645
2.33
1.96
Solution
Margin of Error = Z a/2 * (sd/ Sqrt(n))
Where,
x = Mean
sd = Standard Deviation
a = 1 - (Confidence Level/100)
Za/2 = Z-table value
Z a/2= 2.576
