Question

Suppose that a population is being studied that has a known standard deviation of 34. Further suppose a sample of size 110 is taken, resulting in a sample mean of 340. Determine the Point Estimate and the Margin of Error for a 95% Confidence Interval for this sample. Round all calculations to two (2) decimal places.

Answer 1

population standard deviation: = 34,

Sample size: n= 110,

Sample mean:   = 340,

Confidence level: c = 95%

a)

Point estimate for population mean is sample mean( )

Point Estimate =

Hence,

Point Estimate = 340

b)

formula for Margin of Error is

Where Zc is the z critical value for c = 95%

using normal z table we get critical value as

Zc = 1.96

ME = 6.35387

round to 2 decimals

Margin of error = 6.35