Question

UNILCI Gun) Bob the Wine Quality Control Engineer wishes to determine the population mean potassium bitartrate concentration in wine produced at Tallula's Fine Liquors. Bob studies a sample consisting of 81 wine bottles. He finds the sample mean potassium bitartrate concentration is 0.800 g/L with a sample standard deviation of 0.110 g/L. Construct a 90% two-sided confidence interval on the population mean potassium bitartrate concentration. Give your answer to four decimal places. Show your work.

Answer 1

Answer:

n= 81, = 0.80, s= 0.110, c= 90%

T

formula for confidence interval is

S TĚtc* n

where tc is the t critical value for c= 90%

with df= n-1 =81 -1 = 80

using t table we get,

tc = 1.664

$0.80\pm 1.664* \frac{ 0.110}{ \sqrt{81}}$

0.7797 < $\mu$ < 0.8203

thus we get 90% confidence interval as

( 0.7797 , 0.8203 )