Error in Statistics 1Var Report

[John P]

(01-26-2015 01:42 PM)mark4flies Wrote:  I think that the values for the sample and population standard deviation estimates are switched when using the Stats 1Var app. For example, I open the app and store data 88, 90, 89, 65, 70, and 89 in D1. I press "Stats" and see that sX (sample standard deviation) is 11.2323936 and sigmaX (population standard deviation) is 10.2537256. This answer makes no sense because the bias correction always produces an estimate for the population that is larger than for the sample.

If I use stddev(D1) the estimate is 10.2537256102. If I use stddevp(D1) the estimate is 11.2323936303. I verified these values by hand calculation. So it isn't that the HP Prime calculation is wrong, but that the report in the app is wrong.

Also, if I use Vars > App > Statistics 1Var > Results > sX or sigmaX, I get the wrong value returned. The values for these two estimates are switched in the app.

Hello,

Sample std. dev. has in denominator (n-1) but population std. dev has only (n) so after division sample std. dev. will have greater valu, because smaller number in denominator, than population std. dev.

Cheers