SAMPLE EXCEL PROGRAM

(SEE USE OF NORMSDIST IN THE STATISTICAL FUNCTIONS)

 

1.      Program to determine probabilities associated with a range of values of X given population mean and standard deviation, assuming that X is normally distributed

 

              INTRODUCTION: This program estimate the probability P (X1<X<X2) on the assumption that X is normally distributed give the population mean of X and standard deviation.

             

INSTRUCTION ENTER POPULATION MEAN, STANDARD DEVIATION, X1, AND X2,

 

              a) ENTER MEAN  (ASSUME CELL WHERE MEAN WILL BE PLACED IS J8)

b) ENTER STANDARD DEVIATION (ASSUME CELL WHERE SD WILL BE PLACED IS J9)

c) ENTER X1 (ASSUME THAT THE CELL WHERE X1 WILL BE PLACED IS J10)

             d) ENTER X2 (ASSUME THAT THE CELL WHERE X2 WILL BE PLACED IS J11)

 

                      THEREFORE, Z OF X1 IS _____ HERE USE THE FORMULA +(J10-J18)/J9

                      THEREFORE, Z OF X2 IS _____ HERE USE THE FORMULA  +(J11-J8)/J9

 

                       NOW ASSUME THAT THE Z OF X1 IS IN CELL E13 AND THAT THE CELL OF X2 IS CELL X14

 

                      THEREFORE, PROBABILITY OF A VALUE FROM X1 TO X2 OR P(X1<X<X2) IS ________

 

        TO GET THE PROBABILITY, USE THE FORMULA @NORMSDIST(+E14)-@NORMSDIST(+E13) ON THE CELL

        WHERE THE PROBABILITY IS TO BE PLACED.