HP 39g hp 39g+ (39g & 40g)_mastering the hp 39g+_English_E_F2224-90010.pdf - Page 127

The effect of HRng The effect of HRange is rather different. It controls what range of data is analyzed in calculating the frequencies, and is normally set automatically to be the maximum and minimum values for the data. For example H1 (shown right) has an HRange of -2 to 7. If I go into PLOT SETUP and change this to 0 to 7 then the graph loses the left hand column representing the value of -2. The advantage of this is that it allows you to eliminate outliers from your graph quite easily. However, eliminating them from your graph does not eliminate them from inclusion in the calculation of the values that appear in the page. To do that you would need to use DEL in the NUM view to delete the actual data itself. Grouped data & HWidth One final note concerns grouped data. We saw earlier how to deal with data displayed in a frequency table, but did not deal with the case where the data was also grouped into intervals or classes. data freq For example, suppose we want to analyze the set of 10 - 19 14 grouped data in the table on the right. 20 - 29 26 30 - 39 37 40 - 49 23 The hp 39g+ provides some limited methods to deal 50 - 59 17 with data of this form. Summary statistics can be obtained by entering the mid-points of the intervals as the data values but these will only be approximations, as nature of the data itself does not allow calculation of exact values. Attempting a normal PLOT will produce a series of isolated columns, each with width one unit. The reason for this is that the calculator is assuming that there are 14 values of exactly 15 (the mid-point) because it doesn't realize that the columns extend the width of the interval 10 - 19. 127