Author:
Christine Farr

1. True or False. Justify for full credit.

(a) If the variance from a data set is zero, then all the observations in this data set must

be identical.

(b) P(A AND A^c ) 1, whereA is the complement of A.

(c) The mean is always equal to the median for a normal distribution.

(d) A 99% confidence interval is wider than a 95% confidence interval of the same

parameter.

There are 1000 juniors in a college. Among the 1000 juniors, 200 students are in the

STAT200 roster, and 100 students are in the PSYC300 roster. There are 80 students taking

both courses.

12. What is the probability that a randomly selected junior is taking at least one of these two

courses? (10 pts)

13. What is the probability that a randomly selected junior is taking PSYC300, given that

he/she is taking STAT200? (10 pts)

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