The standard deviation of a binomial distribution is _____. a. ...

[jc611]

The standard deviation of a binomial distribution is _____.
 a. E(x) = pn(1  n)
  b. E(x) = np(1  p)
  c. E(x) = np
  d. None of the answers is correct.

Question 2

The average starting salary of students who graduated from colleges of Business in 2009 was 48,400 . A sample of 100 graduates of 2010 showed an average starting salary of 50,000 . Assume the standard deviation of the population is known to be 8000 . We want to determine whether or not there has been a significant increase in the starting salaries.
 a. State the null and alternative hypotheses to be tested.
  b. Compute the test statistic.
  c. The null hypothesis is to be tested at the 5 level of significance. Determine the critical value for this test.
  d. What do you conclude?
  e. Compute the p-value.

[vseab]

Answer to Question 1

d

Answer to Question 2

a. H0:   48,400
Ha:  > 48,400
b. Test statistic z = 2.0
c. Critical z = 1.645
d. Reject H0 and conclude that there has been a significant increase in the starting salaries.
e. p-value = .0228

[jc611]

Excellent

[fatboyy09]

Thanks for the timely response, appreciate it