# statistics

posted by
**nana** on
.

Suppose it is known that the average score of all high school seniors taking a national test of basic skills is 420. These scores are normally distributed with a standard deviation of 80. A school gives the test to a sample of 144 seniors.

Identify the following characteristics of the sampling distribution for the sample mean (x-bar).

i. the mean

ii. the standard deviation

iii. the shape