The ages of the 5 officers for a school club are 18, 18, 17, 16, and 15. The proportion of officers who are younger than 18 is 0.6. The table displays all possible samples of size 2 and the corresponding proportion for each sample.
Sample n = 2 18, 18 18, 17 18, 17 18, 16 18, 16 18, 15 18, 15 17, 16 17, 15 16, 15
Sample
Proportion
0 0.5
0.5 0.5 0.5 0.5 0.5 1
1
1
Using the proportions in the table, is the sample proportion an unbiased estimator?
Yes, the sample proportions are calculated using samples from the population.
Yes, the mean of the sample proportions is 0.6, which is the same as the population proportion.
No, 0.6 is not one of the possible sample proportions.
No, 70% of the sample proportions are less than or equal to 0.5.

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.