An accounting professor is notorious for being stingy in giving out good letter grades. In a large section of 100 students in the fall semester, she gave out only 3% A's, 13% B's, 52% C's, and 32% D's and F's. Assuming that this was a representative class, compute the 99% confidence interval of the probability of getting at least a B from this professor. Use Z0.005 = 2.576 in your calculation. (You may find it useful to reference the z table.  Round final answers to 3 decimal places.)   Confidentce Interval from _______ to _______

suppose a random sample of 50 basketball players have an average height of 78 inches. Also assume that the population standard deviation is 1.5 inches.  I need to Calculate the 99% 95% 90% 80% and 70% confidence interval.  The thing is my answers using the formula from class isn't giving me the answers my professor posted.

If n=15, ¯xx¯(x-bar)=39, and s=11, construct a confidence interval at a 95% confidence level. Assume the data came from a normally distributed population.Give your answers to one decimal place.

The Athletics Department at a high school is interested in the difference in the run times between 11th and 12th grade students. Suppose the 11th grade students make up the first sample while the 12th grade students make up the second.Using a confidence level of 95%, the confidence interval found was (−1.8,2.9)(-1.8,2.9).Which of the following is the correct interpretation? We are 95% confident that the run times of the 11th grade students are, on average, faster than those of the 12th grade students. We are 95% confident that the run times of the 11th grade students are, on average, slower than those of the 12th grade students. We are 95% confident that the run times of the 11th grade students are, on average, about the same as those of the 12th grade students.