The mean weight of trucks traveling on a particular section of Highway 401 is not known. A provincial highway inspector needs an estimate of the mean. He selects a random sample of 49 trucks passing the weighing station and finds the mean is 15.8 tons, with a standard deviation of the sample of 3.8 tons. What is the 95 percent interval for the population mean?
A) 14.7 and 16.9
B) 13.2 and 17.6
C) 10.0 and 20.0
D) 16.1 and 18.1
E) None of the choices are correct

Question

Quizplus · Accepted Answer

The 95% confidence interval is calculated using the formula: mean ± (Z * (standard deviation/sqrt(n))). Here, Z is 1.96 for 95% confidence, the mean is 15.8, the standard deviation is 3.8, and n is 49. The interval is 15.8 ± (1.96 * (3.8/7)), which is approximately 14.7 to 16.9.

The Mean Weight of Trucks Traveling on a Particular Section