Unteers were divided into two equal-sized groups. each volunteer took a math test that involved transforming strings of eight digits into a new string that fit a set of given rules, as well as a third, hidden rule. prior to taking the test, one group received 8 hours of sleep, while the other group stayed awake all night. the scientists monitored the volunteers to determine whether and when they figured out the rule. of the volunteers who slept, 39 discovered the rule; of the volunteers who stayed awake, 15 discovered the rule. what can you infer about the proportions of volunteers in the two groups who discover the rule? support your answer with a 90% confidence interval.

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.