12) Constructing a confidence interval You must show your work for credit. To show your work . Clearly stated the confidence level, sample size, and point statistic . If you used technology such as Excel or a Tl-84 calculator to generate the confidence interval please attach a picture or write out the commands you entered into the calculator. A researcher is interested in finding a 95% confidence interval for the mean number minutes students are concentrating on their professor during a one hour statistics lecture. The study included 124 students who averaged 33.8 minutes concentrating on their professor during the hour lecture. The standard deviation was 12.6 minutes. Round answers to 3 decimal places where possible. a. To compute the confidence interval use a distribution. b. With 95% confidence the population mean minutes of concentration is between C] and C] minutes. c. If many groups of 124 randomly selected members are studied, then a different confidence interval would be produced from each group. About C] percent of these confidence intervals will contain the true population mean minutes of concentration and about C] percent will not contain the true population mean minutes of concentration. 7) Normal Distribution Computation (show your work for full credit) You must show your work for full credit. You may take a picture of your work and upload it to the "show work" link. Your work should include: 1. Set up the parameter for normal distribution 2. Enter the parameters into the normal distribution formula for each part. Suppose that the speed at which cars go on the freeway is normally distributed with mean 72 mph and standard deviation 6 miles per hour. Let X be the speed for a randomly selected car. Round all answers to decimal places where possible. I a. What is the distribution of X? X ~ N( ) b. If one car is randomly chosen, find the probability that it is traveling more than 69 mph. C] c. If one of the cars is randomly chosen, find the probability that it is traveling between 71 and 76 mph. C] d. 75% of all cars travel at least how fast on the freeway? mph