The mean number of hours of parttime work per week for a sam

The mean number of hours of part-time work per week for a sample of 88 teenagers is 30. If the margin of error for the population mean with a 99% confidence interval is 1.8, construct a 99% confidence interval for the mean number of hours of part-time work per week for all teenagers. Lower endpoint? Upper endpoint?

Solution

CI = x ± Z a/2 * (sd/ Sqrt(n))
Where,
x = Mean
sd = Standard Deviation
a = 1 - (Confidence Level/100)
Za/2 = Z-table value
CI = Confidence Interval
  
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

C.I = x ± M.E
C.I = 30 ± 1.8
C.I = [ 30-1.8, 30+1.8 ] = [ 28.2 , 31.8 ]