rev HP17BII  stat problems and/or 42SX  Printable Version + HP Forums (https://archived.hpcalc.org/museumforum) + Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum1.html) + Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum2.html) + Thread: rev HP17BII  stat problems and/or 42SX (/thread76690.html) 
rev HP17BII  stat problems and/or 42SX  Jose Sanchez  08112005 Any one out there able to provide guidance as to why I can not get the correct answer posted by the book. Using the 17bii I get a different answer (9+) Why the difference, did I leave something out? How do I handle frequencies?
If anyone coudl help otherwise with the 42SX for the same problem. It has been too many years since I use this HP
Re: rev HP17BII  stat problems and/or 42SX  Thomas Radtke  08112005 One result is the sd for the entire population (8...), the other one for a sample from a population (9...). Refer to a statistics textbook. hth,
Thomas
Re: rev HP17BII  stat problems and/or 42SX  James M. Prange (Michigan)  08112005 Actually, the correct population standard deviation for that data set is about 8.16, not 8.85; are you sure that you're using the right numbers? As Thomas pointed out, the sample standard deviation is different, about 9.13 in this case.
Regards, Re: rev HP17BII  stat problems and/or 42SX  Chris Dean  08112005 I agree with Jame's results. The HP17bII+ manual states in Appendix B that the STDEV function calculates the sample standard deviation (divide by root(n1)) whereas the other answer (8.16) is the population standard deviation (divide by root(n)). I am not sure where 8.85 comes from.
Edited: 11 Aug 2005, 10:03 a.m.
Re: rev HP17BII  stat problems and/or 42SX  Jose Sanchez  08112005 The 8.85 is the result derived from the TI83 or TI BA II PLUS.
I do not want to go TI EITHER !!
The answer 8.85 ..... Sum(data) = 230 {32,41,47,53,54} S=1/n *(sqrroot(n(sumx^2) (SumX)^2) Any inputs?
Re: rev HP17BII  stat problems and/or 42SX  Jose Sanchez  08112005 sorry ! Sum X = 230
Re: rev HP17BII  stat problems and/or 42SX  Bob Wang  08112005 Jose: There is an error in your sample set: {32,41,47,53,54} sums to 227 not 230. I get 9.126883367 on my TI83 Plus and TI BAII Plus using the 227 set.
Bob
Converting Sample Sdev to Population Sdev  Marcus von Cube, Germany  08122005 You can convert from one value to the other by a simple calculation: Sdev_{pop}=Sdev_{sam}*SQRT((N1)/N) In your case, multiply the result by SQRT(4/5). The HP11C manual shows a different approach:
Simply add the mean of the data collected so far to the data and recalculate the standard deviation.
Re: Converting Sample Sdev to Population Sdev  Chris Dean  08122005 Have you made sure all your registers/memories are cleared because sum^2 should be 10639 and sum 227. Possibly drastic action but reset the calculator and try again.
Edited: 12 Aug 2005, 9:08 a.m.
Re: Converting Sample Sdev to Population Sdev  Margaret  08122005 9.126883367 is the STD for the sample 8.163332653 is the STD for the population The numbers above come from Excel .. another wonderful technological product, and the formulas are STDEV(range) and STDEVP(range). The difference between the two numbers is a division by SQRT(n) versus SQRT(n1). To verify the results with your preferred HP calculator, just enter the numbers in the key Ó+, and you will all the statistical parameters of the sample and population. Greetings,
