PLS 209 Research Methods                     Name______________________
     Homework5  Normal Curve

                ******* Due October 26, 2009  ********

    For proportions use 5 places to the right of the decimal.

   The mean of a normal distribution is 20 and its standard deviation is 5.

    1. and 2. Calculate the Z scores and then look up the area under the standard
                   form of the normal curve for the following values from the above distribution:

         Value         5,         10.2,         15,          20,          29.8,       35     

        Z-score  ______  ______  ______  ______  ______  ______    

        Area      ______  ______  ______  ______  ______  ______ 
 
    3. What proportion of cases will have scores between 20 & 10.2?
 
 
     4. What proportion of cases will have scores between 20 & 29.8?

 
     5. What proportion of cases will have scores between 10.2 and 29.8?
  

     6. What proportion of cases will have scores between 5 and 15?
 

     7. What proportion of cases will have scores between 5 & 35?
 

     8. What proportion of cases will have scores less than 10.2?
 

     9. What proportion of cases will have scores greater than 29.8?
 

    10. If you randomly select a case from this distribution, how many times out of 100
          will you get a value either less than 10.2 or greater than 29.8?  _________

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