BADM 205    Practice First Test    Major Silver

 

Do ALL of the following problems.  You may use your notes, textbook and calculator. 

 

1.         A random sample of demerits earned by six for the last demerit period revealed the following values:

 

              12    20    0    8    12    5 

 

a)         Calculate the sample mean, median, mode, range and standard deviation for the number of demerits of the twelve cadets sampled.

 

b)         If it is later determined that the mean and standard devia­tion of the population from which these values were drawn are 12 and 4 demerits, respectively,

 

            i) what can be said about the probability that a cadet earned more than between 20 demerits during the period?

 

            how would you change your answer to part i) if you know that the population is mound-shaped?

           

2.         Let P(A) = .8, P(B) = .4, P(Ac or B) = .6

 

a.         Calculate the probabilities of the following events:

 

            A or B     A and Bc      Ac  or Bc

 

b.         Are A and B mutually exclusive? Why or why not?

 

c.         Are A and B independent?  Why or why not?

 

 

3.         A recent survey of Lowcountry business people revealed that 80 percent of the retailers and 50 percent of the manufac­turers feel the Naval Base closures had a serious impact on their businesses.  70 percent of those sampled were in the retail sector; the rest were manufacturers.

 

            What fraction of all businesses felt they had been seriously impacted by the closures?

 

            What fraction of those business people who felt the closures seriously impacted their businesses are retailers?