calculate with confidence level 97%, Have fun and be creative with it and calculate another T-confidence interval and interpret your results. Compare your results to that of the initial 95%, how much do they differ? How useful can this type of information be when you go to buy a new car, or even a house? For this week's exercise, we were tasked with using our car prices information to calculate two 95% confidence intervals. For the first interval, I calculated a T-critical value of 2.262157. From here, we now have everything we need. I then used the following equation with my mean and standard deviation: 25,931.20 +/- 2.262157(29,147.60463 / square root of 10). The outcomes, depending on the adding or subtracting of the mean and product of T x (SD / square root of 10), were 5,080 and 46,782. With these outcomes, we are 95% confident that the population mean car price for the type of cars I selected during week 1 is between $5,080 and $46,782. Next, we were tasked with calculating a proportion confidence interval using the proportion of the number of cars that fall below the average. For this, we need to calculate a Z-critical value. Using Excel, we can find that the Z-critical value for a 95% confidence interval is 1.96. Then, to find the answer, I used my information in the following equation: .5 +/- 1.96(square root of [.5 x .5] / 10). The two outcomes to this equation were .19009679 and .80990