Complete the following:
Q1: It involve the random variable x with probability distribution given below.
x -2 4 5 6 7
P(x) 0.15 0.05 0.3 0.1 0.4
Determine the expected value of x.
Determine the standard deviation of x.
Q2: Below is a compilation of student distribution in our four statistics classes from the summer of 2009.
Course stat 200 stat 225 stat 230 stat 250
Percentage 45.8 12.0 32.8 9.4
Q3: The enrollment report for the summer of 2011 is given as follows
Course stat 200 stat 225 stat 230 stat 250
Frequency 249 71 133 47
At the 1% significant level, do the data provide sufficient evidence to conclude that 2011's enrollment distribution differs from the 2009 distribution?
Show all work: include the hypotheses, the computation of the test statistic, state the critical value, and state the conclusion of the test.