The US Dairy Industry wants to estimate the mean yearly milk
The U.S. Dairy Industry wants to estimate the mean yearly milk consumption. A sample of 16 people reveals the mean yearly consumption to be 60 gallons with a standard deviation of 20 gallons.
(a-1)
What is the value of the population mean?
(a-2)
What is the best estimate of this value?
(c)
For a 90 percent confidence interval, what is the value of t? (Round your answer to 3 decimal places.)
(d)
Develop the 90 percent confidence interval for the population mean. (Round your answers to 3 decimal places.)
| The U.S. Dairy Industry wants to estimate the mean yearly milk consumption. A sample of 16 people reveals the mean yearly consumption to be 60 gallons with a standard deviation of 20 gallons. | 
Solution
Confidence Interval
 CI = x ± t a/2 * (sd/ Sqrt(n))
 Where,
 x = Mean
 sd = Standard Deviation
 a = 1 - (Confidence Level/100)
 ta/2 = t-table value
 CI = Confidence Interval
 a.1)
 Mean(x)=60
 Standard deviation( sd )=20
 Sample Size(n)=16
 c) t = 1.753
 d)
Confidence Interval = [ 60 ± t a/2 ( 20/ Sqrt ( 16) ) ]
 = [ 60 - 1.7531 * (5) , 60 + 1.7531 * (5) ]
 = [ 51.235,68.766]

