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I am experiencing the same problem in both Excel 2002 and 2003.
The CHITEST worksheet function is "sometimes" returning #NUM! instead of a number. CHITEST syntax is CHITEST(actual_range,expected_range) I am running CHITEST against 6 ranges of numbers - 10,000 numbers in each range. The expected range is always the same, for all of my CHITEST instances. One of the six ranges is returning #NUM!, the other 5 return a number(as I expect). I looked up the meaning of #NUM! - one listed cause is that some of the arguments are not numbers. I ran the COUNT function against the range - COUNT thinks they are all numbers. So, I ran CHITEST on a some sub-ranges of the range where CHITEST returns #NUM!. Example: Range of numbers RESULT 1-10,000 #NUM! 1-30 number 1-100 number 1-1000 number 1-2000 #NUM! 1001-2000 #NUM! 1001-1500 number 1501-2000 number I am stumped about why CHITEST would return a number for the sub-ranges 1001-1500 AND 1501-2000 but NOT for the sub-range 1001-2000. What am I missing? |
#2
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You have not given enough information to diagnose the problem. As a guess,
your data puts you into an area where CHIDIST fails. Help for CHITESTdocuements the calculation for the chi-square statistic and its degrees of freedom. For more information, reply back with the calculated chi-square statistic and degrees of freedom, if you don't want to reply back with the actual data. Those are passed to CHIDIST to evaluate the p-value. However CHIDIST(df-e,df) returns #VALUE instead of a p-value near 0.5 for even moderately large df and small e0. For example, =CHIDIST(799,800) returns #NUM. If you manually calculate the chi-square statistic and degrees of freedom, you could use comp_cdf_chi_sq() from Ian Smith's probability function library at http://members.aol.com/iandjmsmith/examples.xls Jerry "fred_y_Ohio" wrote: I am experiencing the same problem in both Excel 2002 and 2003. The CHITEST worksheet function is "sometimes" returning #NUM! instead of a number. CHITEST syntax is CHITEST(actual_range,expected_range) I am running CHITEST against 6 ranges of numbers - 10,000 numbers in each range. The expected range is always the same, for all of my CHITEST instances. One of the six ranges is returning #NUM!, the other 5 return a number(as I expect). I looked up the meaning of #NUM! - one listed cause is that some of the arguments are not numbers. I ran the COUNT function against the range - COUNT thinks they are all numbers. So, I ran CHITEST on a some sub-ranges of the range where CHITEST returns #NUM!. Example: Range of numbers RESULT 1-10,000 #NUM! 1-30 number 1-100 number 1-1000 number 1-2000 #NUM! 1001-2000 #NUM! 1001-1500 number 1501-2000 number I am stumped about why CHITEST would return a number for the sub-ranges 1001-1500 AND 1501-2000 but NOT for the sub-range 1001-2000. What am I missing? |
#3
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Based on Jerry's advice,...
For my set of 10,000 numbers, using Excel's CHITEST help documentation, I manually calculated the chi-square statistic (9,717) and degrees of freedom (9,999). I then used those values as parameters for Excel's CHIDIST function, CHIDIST(9717,9999). Result from Excel is #NUM! . Excel's help documentation for CHITEST and CHIDIST do not state any limitations for those two functions' parameters. Smells like a bug to me....... .....(....or is Microsoft gonna dismiss this an "undocumented FEATURE".) Conclusion: CHITEST and CHIDIST do not always work as documented. "Jerry W. Lewis" wrote: You have not given enough information to diagnose the problem. As a guess, your data puts you into an area where CHIDIST fails. Help for CHITESTdocuements the calculation for the chi-square statistic and its degrees of freedom. For more information, reply back with the calculated chi-square statistic and degrees of freedom, if you don't want to reply back with the actual data. Those are passed to CHIDIST to evaluate the p-value. However CHIDIST(df-e,df) returns #VALUE instead of a p-value near 0.5 for even moderately large df and small e0. For example, =CHIDIST(799,800) returns #NUM. If you manually calculate the chi-square statistic and degrees of freedom, you could use comp_cdf_chi_sq() from Ian Smith's probability function library at http://members.aol.com/iandjmsmith/examples.xls Jerry "fred_y_Ohio" wrote: I am experiencing the same problem in both Excel 2002 and 2003. The CHITEST worksheet function is "sometimes" returning #NUM! instead of a number. CHITEST syntax is CHITEST(actual_range,expected_range) I am running CHITEST against 6 ranges of numbers - 10,000 numbers in each range. The expected range is always the same, for all of my CHITEST instances. One of the six ranges is returning #NUM!, the other 5 return a number(as I expect). I looked up the meaning of #NUM! - one listed cause is that some of the arguments are not numbers. I ran the COUNT function against the range - COUNT thinks they are all numbers. So, I ran CHITEST on a some sub-ranges of the range where CHITEST returns #NUM!. Example: Range of numbers RESULT 1-10,000 #NUM! 1-30 number 1-100 number 1-1000 number 1-2000 #NUM! 1001-2000 #NUM! 1001-1500 number 1501-2000 number I am stumped about why CHITEST would return a number for the sub-ranges 1001-1500 AND 1501-2000 but NOT for the sub-range 1001-2000. What am I missing? |
#4
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I agree that CHIDIST (and hence CHITEST) should be able to handle this
calculation, but thus far, MS has not seen fit to use a better algorithm. As I noted previously, there is a freely availabe VBA library of probability functions that are as good or better than any double precision implementation I have seen (including those in dedicated statistics packages and commercial numerical libraries). http://members.aol.com/iandjmsmith/examples.xls Using that library, =comp_cdf_chi_sq(9717,9999) returns 0.977703672596211, which is correct to all figures that Excel can display. Jerry "fred_y_Ohio" wrote: Based on Jerry's advice,... For my set of 10,000 numbers, using Excel's CHITEST help documentation, I manually calculated the chi-square statistic (9,717) and degrees of freedom (9,999). I then used those values as parameters for Excel's CHIDIST function, CHIDIST(9717,9999). Result from Excel is #NUM! . Excel's help documentation for CHITEST and CHIDIST do not state any limitations for those two functions' parameters. Smells like a bug to me....... ....(....or is Microsoft gonna dismiss this an "undocumented FEATURE".) Conclusion: CHITEST and CHIDIST do not always work as documented. "Jerry W. Lewis" wrote: You have not given enough information to diagnose the problem. As a guess, your data puts you into an area where CHIDIST fails. Help for CHITESTdocuements the calculation for the chi-square statistic and its degrees of freedom. For more information, reply back with the calculated chi-square statistic and degrees of freedom, if you don't want to reply back with the actual data. Those are passed to CHIDIST to evaluate the p-value. However CHIDIST(df-e,df) returns #VALUE instead of a p-value near 0.5 for even moderately large df and small e0. For example, =CHIDIST(799,800) returns #NUM. If you manually calculate the chi-square statistic and degrees of freedom, you could use comp_cdf_chi_sq() from Ian Smith's probability function library at http://members.aol.com/iandjmsmith/examples.xls Jerry "fred_y_Ohio" wrote: I am experiencing the same problem in both Excel 2002 and 2003. The CHITEST worksheet function is "sometimes" returning #NUM! instead of a number. CHITEST syntax is CHITEST(actual_range,expected_range) I am running CHITEST against 6 ranges of numbers - 10,000 numbers in each range. The expected range is always the same, for all of my CHITEST instances. One of the six ranges is returning #NUM!, the other 5 return a number(as I expect). I looked up the meaning of #NUM! - one listed cause is that some of the arguments are not numbers. I ran the COUNT function against the range - COUNT thinks they are all numbers. So, I ran CHITEST on a some sub-ranges of the range where CHITEST returns #NUM!. Example: Range of numbers RESULT 1-10,000 #NUM! 1-30 number 1-100 number 1-1000 number 1-2000 #NUM! 1001-2000 #NUM! 1001-1500 number 1501-2000 number I am stumped about why CHITEST would return a number for the sub-ranges 1001-1500 AND 1501-2000 but NOT for the sub-range 1001-2000. What am I missing? |
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