A consumer group conducted a study of SUV owners to estimate the mean highway mileage for their vehicles. A simple random sample of 91 SUV owners was selected, and the owners were asked to report their highway mileage. The following results were summarized from the sample data:

x = 21.3 mpg s = 6.3 mpg Based on these sample data, compute and interpret a 90% confidence interval estimate for the mean highway mileage for SUVs.