Consider a vending machine that is supposed to dispense eight ounces of soft drink. A random sample of 20 cups taken over a one-week period had an average of 7.845 ounces, and a standard deviation of 0.1986. Estimate a 95% confidence interval of the true mean dispensed by the machine and interpret (in a sentence) what it means.
Given Data
Sample Size = n = 20
Degree of Freedom = n-1 = 20-1 = 19
Sample Mean = x = 7.845
Sample Standard Deviation = s = 0.1986
At 95% confidence interval level of significance = α = 0.05
Critical value of t using excel formula =T.INV.2T(0.05,19)
tc = 2.093
The 95% confidence for the population mean μ is computed using the following formula.
95% confidence interval of the true mean dispensed by the machine is
confidence interval refers to the probability that a population parameter will fall between two set values. So here it means for 95% confidence interval the population mean of soft drink dispense can fall in between of 7.752 ounces to 7.938 ounces.
Get Answers For Free
Most questions answered within 1 hours.