Hp12c Solutions

[Don Geronimo]

Anyone out there have HP12C solution or formulas for COD, COV, etc. Thanks

 

[Deleted member 134708]

Easy peasy.

In reverse polish notation (only way I use) for sample covariance

Sample data sets:

x -- 10 -- 20 -- 30 -- 40 -- 50 -- 60 -- 70

y -- 1 -- 2 -- 3 -- 4 -- 5 -- 6 -- 7

*Clear register/calculator*

1 enter 10 sigma
2 enter 20 sigma
3 enter 30 sigma
4 enter 40 sigma
5 enter 50 sigma
6 enter 60 sigma
7 enter 70 sigma
g, s, X, enter
g, number 2 key
R↓, X

display should read 46.66

for population variance continue with:
RCL, 1, 1, - RCL, 1
÷, X

display should read 40.00

 

[argllc]

Not exactly what you asked for, but this simple hp12c program will give you x (mean), s (std. dev.) & cov (coefficient of var.) with a pause in between:
f p/r
g x (mean)
sto 7
g pse
g s (std. dev.)
enter
g pse
rcl 7
/ (divide)
f p/r
(to use, enter # then sigma plus....repeat....& when done, hit r/s)
I wrote it just to play around with the hp12c and learn about programming it, but it actually turned out to be useful to me in classes and, occasionally, the real world as a minor shortcut.

 

[Deleted member 134708]

Unless you have to do this for a test, you're better off with excel. For Real Estate I'd think standard deviation, correlation coefficient and coefficient of determination would be most applicable.

Correlation: House Price X = $100k, $200k, $300k
Rent Y = $1,000, $1,200, $1,300

$100K, enter, $1,000, sigma
$200K, enter, $1,200, sigma
$300K, enter, $1,300, sigma
1, g, number 1 key, x><y key (above STO)

Display should read 0.9819 which is extremely correlated. A lot of people don't do this next step but it is useful. Square 0.9819 = 0.9642 which is called the coefficient of determination. It is essentially the % of variations that can be explained. So 96% of the data can be explained and 4% cannot.

Standard deviation is simple enough not to write here. It's good to use to give reasoning for not using certain data as you can show to the reader it is outside 1 standard deviation. Example, if have 10 rents and SD is $500 from a mean of $2,000, than anything less than $1,500 or greater than $2,500 can be shown as 2-3 SD move and didn't use those data points. If add frequencies it's a little longer in the tooth and don't see much use other than a test. If want I can write it out, not that long but not worth it if not asking.

I use standard deviation all the time for finance/options.