will We make calculations using Poisson probability mass function for Example 4 on page 61. This time we won't bother to make a table and graph as in the previous example, although this could be done. Calculate a value of the mass function: Click cell F3 or any open cell where you would like to enter the computations. Now we will enter the Poisson probability mass function: p( y ) =
e - y y!
Click the fx (function wizard button) on the toolbar Choose the Statistical function category: on the left, and the POISSON function name on the right of the Paste Function input screen Click OK Fill in the POISSON input screen as follows: X 2 this is the value of y in Example 4 Mean 1.2 this is in Example 4 Cumulative 0 = FALSE this chooses the mass function rather than the CDF Click OK, you will see the 0.2169 = p(2) = Probability of 2 defects in a one hundred foot section in cell F3 (or the cell of the spreadsheet you have selected). The second part of Example 4 shows calculation of the Probability of 3 or more defects in a one hundred foot section. Let's use the EXCEL POISSON function to calculate this probability. Calculate a value of the CDF: Click cell F3 or open any cell where you would like to enter the computations. Now we will enter the Poisson CDF: F ( y ) =
k =0 y
e - k k!
Choose the Statistical function category: on the left, and the POISSON function name on the right of the Paste Function input screen Click OK Fill in the POISSON input screen as follows: X 2 this is the value of y in Example 4 Mean 1.2 this is in Example 4 Cumulative 1 this chooses the CDF rather than the mass function Click OK, you will see the 0.8795 = F(2) = Probability of 2 defects or less in a one hundred foot section in cell F3 (or the cell of the spreadsheet you have selected). Calculate Probability of 3 or more: Look at the formula bar and you will see the formu...