Suppose the population standard deviation is 5 and SRS of n1

Suppose the population standard deviation is 5, and SRS of n=100 is obtained, and the confidence level is chosen to be 98%. The margin of error for estimating a mean is given by:

a. 1.1650

b. 0.1228

c. 0.1165

d. 1.2280

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
Mean(x)=18.6
Standard deviation( sd )=5
Sample Size(n)=100
Margin of Error = Z a/2 * 5/ Sqrt ( 100)
= 2.33 * (0.5)
= 1.1650