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 mean. He selects a random sample of 49 trucks passing the weighing station and finds the mean weight is 15.8 tons. The population standard deviation is 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

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 95% confidence (1.96), σ is the population standard deviation, and n is the sample size. Plugging in the values: 15.8 ± (1.96 * (3.8/√49)) gives the interval 14.7 to 16.9.

The Mean Weight of Trucks Traveling on a Particular Section