The Inka Kola Soda Company has heard cmp1aints that the amou

The Inka Kola Soda Company has heard cmp1aints that the amount of soda in their 12-oz. cans is less than 12 ounces. A random sample of 36 12-oz soda cans is taken, resulting in a sample mean of 11.85 oz and a sample standard deviation of s = .18 oz. Assuming that the population is normal, a 95% confidence interval for the true mean amount of soda in a 12-oz can will be a. 11.85 plus or minus 0.0494 b. 11.85 plus or minus 0.0588 c. 11.85 plus or minus 0.0609 d. 11.85 plus or minus 0.0784

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
Mean(x)=11.85
Standard deviation( sd )=0.18
Sample Size(n)=36
Confidence Interval = [ 11.85 ± t a/2 ( 0.18/ Sqrt ( 36) ) ]
= [ 11.85 - 2.0301 * (0.03) , 11.85 + 2.0301 * (0.03) ]
= [ 11.85 - 0.0609,11.85 + 0.0609 ]