Final answer:
To find a 95% confidence interval for the mean price of regular gasoline in a region, use the formula: Confidence Interval = (sample mean) ± (critical value) × (standard deviation / square root of sample size). Use the t-distribution to find the critical value since the population standard deviation is unknown. Substitute the given values into the formula to calculate the confidence interval.
Step-by-step explanation:
A 95% confidence interval for the mean price of regular gasoline in the region can be calculated using the formula:
Confidence Interval = (sample mean) ± (critical value) × (standard deviation / square root of sample size)
Since the population standard deviation is unknown, we can use the t-distribution to find the critical value. The number of degrees of freedom is the sample size minus 1. We can then substitute the given values into the formula to calculate the confidence interval.