Astatistics professor has observed that for several years students score an average of 105 points out of 150 on the semester exam. a salesman suggests that he try a statistics software package that gets students more involved with computers, predicting that it will increase students' scores. the software is expensive, and the salesman offers to let the professor use it for a semester to see if the scores on the final exam increase significantly. the professor will have to pay for the software only if he chooses to continue using it. a) is this a one tailed or two tailed test? explain. b) write the null and alternative hypotheses: c) in this context, explain what would happen if the professor makes a type 1 errord) in this context, explain what would happen if the professor makes a type 2 error:

Determine if the following statement is true or false. the normal curve is symmetric about its​ mean, mu. choose the best answer below. a. the statement is false. the normal curve is not symmetric about its​ mean, because the mean is the balancing point of the graph of the distribution. the median is the point where​ 50% of the area under the distribution is to the left and​ 50% to the right.​ therefore, the normal curve could only be symmetric about its​ median, not about its mean. b. the statement is true. the normal curve is a symmetric distribution with one​ peak, which means the​ mean, median, and mode are all equal.​ therefore, the normal curve is symmetric about the​ mean, mu. c. the statement is false. the mean is the balancing point for the graph of a​ distribution, and​ therefore, it is impossible for any distribution to be symmetric about the mean. d. the statement is true. the mean is the balancing point for the graph of a​ distribution, and​ therefore, all distributions are symmetric about the mean.