HP 42S - 9 Statistics

Example: Calculate
∫
1
0
2
dxx
First we enter the function as a program
01 LBL “FX”
02 MVAR “X” (also available in ∫f(x) menu)
03 RCL X
04 X↑2
05 RTN
06 END
Then we go to the ∫f (x) menu and what we see is “Select ∫f(x) Program”. In our case we select FX
then what appears is “Set Vars; Select ∫var” and we select X (before that we may set some
variables/constants if needed) and then we have to set LLIM (lower limit), ULIM (upper limit) and
ACC (Accuracy factor). In our case LLIM-0 and ULIM=1 and for ACC we can use 0.001. Now just
press ∫ and we find 0.33333028. If we set ACC to 0.000001 we will have 0.33333333333. In the
Free42 program the results may be little different.
9 Statistics
To enter statistical data we use the function Σ+. For one variable statistic just enter the number and
press Σ+. For two variables statistic first enter y, press ENTER and then enter x (without pressing
ENTER) and finally press Σ+. To clear statistics data just do  CLEAR CLΣ.
The statistical functions are available in  STAT menu and they are:
Σ+: The same of pressing Σ+.
SUM: Calculates the sum of the statistical data.
MEAN: Calculates the mean of the statistical data.
WMN: Calculates the weighted mean (x weighted by y).
SDEV: Sample standard deviation. (To calculate the Population standard deviation you must calculate
the mean, add it to statistical data and then press SDEV)
CFIT: This is a sub-menu to fit the data in linear regression, logarithm regression, exponential
regression or power regression.
There is also a second line with ALL, LINΣ, ΣREG and ΣRG? Functions.
Example: A particle of mass m
1
= 1 kg is at the position x
1
= 2m while a particle of mass m
2
=3 kg is
at position x
2
= 6m. What is the position of the center of the mass?
Solution: The position of the center of the mass is given by
21
2211
mm
xmxm
x
+
+
=
This is a weighted mean where the physical mass is the statistical weight. To calculate it using HP-
42S we do:
 CLEAR CLΣ (clearing statistical data)