A test engineer wants to estimate the mean gas mileage (in miles per gallon) for

Question

A test engineer wants to estimate the mean gas mileage (in miles per gallon) for a particular model of automobile. Eleven of these cars are subjected to a road test, and the gas mileage is computed for each car. A dotplot of the 11 gas-mileage values is roughly symmetrical and has no outliers. The mean and standard deviation of these values are 25.5 and 3.01, respectively. Assuming that these 11 automobiles can be considered a simple random sample of cars of this model, which of the following is a correct statement? 3.01 11 AA 95% confidence interval for is 25.5 ±2.2284 3.01 BA 95% confidence interval for is 25.5±2.201 3.01 CA 95% confidence interval for is 25.5±2.228 10 3.01 D. A 95% confidence interval for is 25.5±2.201 10 E.The results cannot be trusted; the sample is too small.

Explanation / Answer

Given :-

Mu =25.5 , sigma = 3.01 , n=11

Here n is small that n< 30 then we can use the t-test critical value

tc = 95 % confidence level at alpha= 5% and df=n-1 = 11-1 =10

then critical value is 2.201

Therefore 95% confidence interval for mu is ,

Option "B" is correct.

Mu is [25.5 +/- (2.201*3.01/11)]

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.