The mean weight of trucks traveling on a particular section of I-475 is not known. A state highway inspector needs an estimate of the population mean. He selects and weighs a random sample of 49 trucks and finds the mean weight is 15.8 tons. The population standard deviation is 3.8 tons. What is the 95% confidence 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

Question

Quizplus · Accepted Answer

The 95% confidence interval for the population mean is calculated using the formula: mean ± (Z * (σ/√n)), where Z is the Z-score for the desired confidence level (1.96 for 95%), σ is the population standard deviation, and n is the sample size. Here, it's 15.8 ± (1.96 * (3.8/√49)), which simplifies to 15.8 ± 1.1, giving us the interval 14.7 to 16.9.

The Mean Weight of Trucks Traveling on a Particular Section