An environmental group at a local college is conducting independent tests to determine the distance a particular make of automobile will travel while consuming only 1 gallon of gas.A sample of five cars is tested and a mean of 28.2 miles is obtained.How many cars should the environmental group test if they wish to estimate $\mu$,mean miles per 1 gallon,to within 0.5 miles and be 99% confident? Assume a population standard deviation of 2.7 miles.
A)25
B)124
C)194
D)618
E)619

Question

Quizplus · Accepted Answer

To determine the sample size needed, use the formula for sample size in estimating a population mean: n = (Z*σ/E)^2, where Z is the Z-value for the desired confidence level (2.576 for 99%), σ is the population standard deviation (2.7), and E is the margin of error (0.5). Plugging in these values gives n ≈ 194.

An Environmental Group at a Local College Is Conducting Independent μ\muμ

An Environmental Group at a Local College Is Conducting Independent $\mu$