Due to environmental concerns and the never-ending volatility of gas prices, drivers are becoming more concerned with their cars' as oline consumption.
Cameron White, a research analyst at a nonprofit organization, shares these concerns and wonders whether his car's gas consumption is as efficient as it was when he first bought the new car five years ago. Despite his best intentions, he has been a bit lax in his upkeep of the car and feels that this may adversely influence its performance. At the time he purchased the car, he was told that his car would average 29 miles per gallon (mpg) on highways with a standard deviation of 1 mpg. He records his car's mpg from the last 20 fill-ups and obtains the following values.

In a report, use the above information to:
1. Construct the 95% confidence interval for the population standard deviation. Discuss any assumptions you made for the analysis.
2. Determine whether the variability has significantly increased from the original standard deviation of 1 mpg at a 5% level of significance.

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