HP 17bII manual Weighted Mean and Grouped Standard Deviation, 138 10 Running Total and Statistics

Weighted Mean and Grouped Standard Deviation

Data in one list (x) can be weighted or grouped (by frequency) by data in another list (y). To find the mean of weighted data and the standard deviation of grouped data:

1.Enter the data values―the x-variable―into a SUM list.

2.Enter the corresponding weights or frequencies―the y-variables―into another list. (To calculate G.SD, the y-values should be integers.)

3.From the SUM menu, press E)—to display a menu of SUM-list names. The current list is ˜unless named otherwise.

4.Press the menu key for the list of x-values.

5.Now select the list with the weights (or frequencies) (y).

6.To calculate the weighted mean, press )Ÿ.

7.To calculate the grouped standard deviation, press .

Example: Weighted Mean. A survey of 266 one-bedroom rental apartments reveals that 54 of them rent for $200 per month, 32 for $205, 88 for $210, and 92 for $216. What is the average monthly rent and its standard deviation?

Create two SUM lists. The first, called RENT, should contain the numbers 200, 205, 210, and 216, in that order. The second can be unnamed and should contain the numbers 54, 32, 88, and 92, in that order.

Keys:Display:Description:

$"

@c		"	Clears current list or gets a
W		"	new one.
or		"
		;:H0L#T8U"
p	s
200 I		"	Stores rents into a list.
205 I		"
210 I		"

138 10: Running Total and Statistics

File name : 17BII-Plus-Manual-E-PRINT-030709 Print data : 2003/7/11