A random sample of 25 roundtrip flights between Philadelphia and Dallas has an average airfare of $393.50 with a sample standard deviation of $50.30. The margin of error for a 90% confidence interval around this sample mean is -----.
A)22.9
B)14.1
C)10.6
D)17.2

Question

Quizplus · Accepted Answer

The margin of error (ME) for a confidence interval can be calculated using the formula: ME = z * (σ/√n), where z is the z-score corresponding to the desired confidence level (for 90% confidence, z ≈ 1.645), σ is the sample standard deviation, and n is the sample size. Plugging in the given values: ME = 1.645 * (50.3/√25) = 1.645 * 10.06 ≈ 17.2.

A Random Sample of 25 Roundtrip Flights Between Philadelphia and Dallas