Read carefully and choose only one option
A statistic is an unbiased estimator of a parameter when (a) the statistic is calculated from a random sample. (b) in a single sample, the value of the statistic is equal to the value of the parameter. (c) in many samples, the values of the statistic are very close to the value of the parameter. (d) in many samples, the values of the statistic are centered at the value of the parameter. (e) in many samples, the distribution of the statistic has a shape that is approximately Normal
Scores for a common standardized college aptitude test are normally distributed with a mean of 490 and a standard deviation of 103. Randomly selected students are given a Test Preparation Course before taking this test. Assume, for sake of argument, that the preparation course has no effect.
If 1 student is randomly selected, find the probability that their score is at least 527.3.
P(X > 527.3) =
If 11 students are randomly selected, find the probability that their mean score is at least 527.3.
P(¯¯¯X > 527.3) =