Rational Thinking

Name:

 
 

Class:

 
 

1)  What are 2 ways in which probability can be used?  Explain how they differ?

 
 
 
 
 
 
 
 
 

2)  Explain how the base rate of any particular outcome is calculated.  Why is the

     base rate the best prediction of the future likelihood of that outcome?
 
 
 
 
 
 
 
 
 

3)  Assume 1500 students took a psychology course last semester.  300 students

     earned an A. 650 students earned a B.  425 students earned a C. 25 students
     earned a D.  The rest failed.  What is the probability that that you will receive a B
     in the course (ignoring all other factors such as your interest in the course, amount
     of time spent studying, etc.).
 
 
 
 
 
 
 
 
 

4)  Now assume that 35% of the students who earned a B were 21 or younger.  If you

     were 20 what is the probability of earning a B?
 
 
 
 
 
 
 
 
 

5)  How would you convert the problem to a frequency problem?