HP HP12C hp 12c_user's guide_English_E_HDPMBF12E44.pdf - Page 77

Section 6: Statistics Functions 77 The table below shows where the accumulated statistics are stored. Register Statistic R1 (and display) R2 R3 R4 R5 R6 n: number of data pairs accumulated. Σx: summation of x-values. Σx2: summation of squares of x-values. Σy: summation of y-values. Σy2 summation of squares of y-values. Σxy: summation of products of x-values and y-values. Correcting Accumulated Statistics If you discover you have entered data incorrectly, the accumulated statistics can easily be corrected: z If the incorrect data point or data pair has just been entered and _ has been pressed, press gFg^. z If the incorrect data point or data pair is not the most recent one entered, key in the incorrect data point or data pair again as if it were new, but press g^ instead of _. These operations cancel the effect of the incorrect data point or data pair. You can then enter the data correctly, using _, just as if it were new. Mean Pressing gÖ calculates the means (arithmetic averages) of the x-values ( x ) and of the y-values ( y ). The mean of the x-values appears in the display after Ö is pressed; to display the mean of the y-values, press ~. Example: A survey of seven salespersons in your company reveals that they work the following hours a week and sell the following dollar volumes each month. How many hours does the average salesperson work each week? How much does the average salesperson sell each month? File name: hp 12c_user's guide_English_HDPMBF12E44 Printered Date: 2005/7/29 Page: 77 of 209 Dimension: 14.8 cm x 21 cm