You Are Interested in Purchasing a New Car

You are interested in purchasing a new car. One of the many points you wish to consider is the resale value of the car after 5 years. Since you are particularly interested in a certain foreign sedan, you decide to estimate the resale value of this car with a 90% confidence interval. You manage to obtain data on 17 recently resold 5-year-old foreign sedans of the same model. These 17 cars were resold at an average price of $12,630 with a standard deviation of $800. Suppose that the interval is calculated to be ($12,291.23, $12,968.77) . How could we alter the sample size and the confidence coefficient in order to guarantee a decrease in the width of the interval?

A) Decrease the sample size but increase the confidence coefficient.
B) Increase the sample size and increase the confidence coefficient.
C) Keep the sample size the same but increase the confidence coefficient.
D) Increase the sample size but decrease the confidence coefficient.