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Re: bug: p-value > 1.0 for paired t-test
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From: |
John Darrington |
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Subject: |
Re: bug: p-value > 1.0 for paired t-test |
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Date: |
Thu, 12 Nov 2009 18:05:37 +0000 |
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User-agent: |
Mutt/1.5.18 (2008-05-17) |
This bug was fixed some time ago. See
http://savannah.gnu.org/bugs/index.php?26936
Obviously it didn't make it into the copy that you have.
You can work around it by reversing the order of the pair.
J'
On Thu, Nov 12, 2009 at 03:54:36PM +0000, William Simpson wrote:
Windows version 0.7.2
Data file attached
paired t-test results (see tail end for screwy p-value > 1.0):
1.1 T-TEST. Paired Sample Statistics
#==========#======#==#==============#========#
# # Mean | N|Std. Deviation|SE. Mean#
#==========#======#==#==============#========#
#Pair 0 dc #365.84|18| 69.31| 16.34#
# dnc#366.52|18| 77.33| 18.23#
#Pair 1 pc #372.82|18| 66.64| 15.71#
# pnc#362.14|18| 65.03| 15.33#
#==========#======#==#==============#========#
1.2(2) T-TEST. Paired Samples Correlations
#======#========#==#===========#====#
# | # N|Correlation|Sig.#
#======#========#==#===========#====#
#Pair 0|dc & dnc#18| .98| .00#
#Pair 1|pc & pnc#18| .98| .00#
#======#========#==#===========#====#
1.3(1:2) T-TEST. Paired Samples Test
#==============#==========================================#
# # Paired Differences #
# #-----+--------------+---------------+-----#
# # | | | 95% #
# # | | +-----#
# # Mean|Std. Deviation|Std. Error Mean|Lower#
#==============#=====#==============#===============#=====#
#Pair 0dc - dnc# -.68| 18.06| 4.26|-9.66#
#Pair 1pc - pnc#10.68| 13.29| 3.13| 4.07#
#==============#=====#==============#===============#=====#
1.3(2:2) T-TEST. Paired Samples Test
#=====#====#==#===============#
# | | | #
#-----+ | | #
# | | | #
#-----+ | | #
#Upper| t |df|Sig. (2-tailed)#
#=====#====#==#===============#
# 8.30|-.16|17| .87#
#17.29|3.41|17| 2.00#
#=====#====#==#===============#
2.1 T-TEST. Paired Sample Statistics
#==========#======#==#==============#========#
# # Mean | N|Std. Deviation|SE. Mean#
#==========#======#==#==============#========#
#Pair 0 dc #370.20|17| 68.85| 16.70#
# dnc#372.61|17| 75.13| 18.22#
#Pair 1 pc #376.36|17| 66.92| 16.23#
# pnc#365.79|17| 65.10| 15.79#
#==========#======#==#==============#========#
2.2 T-TEST. Paired Samples Correlations
#======#========#==#===========#====#
# | # N|Correlation|Sig.#
#======#========#==#===========#====#
#Pair 0|dc & dnc#17| .98| .00#
#Pair 1|pc & pnc#17| .98| .00#
#======#========#==#===========#====#
2.3(1) T-TEST. Paired Samples Test
#==============#=================================================#====#==#
# # Paired Differences | | #
# #-----+--------------+---------------+------------+ | #
# # | | | 95% | | #
# # | | +------+-----+ | #
# # Mean|Std. Deviation|Std. Error Mean| Lower|Upper| t |df#
#==============#=====#==============#===============#======#=====#====#==#
#Pair 0dc - dnc#-2.41| 17.01| 4.12|-11.16| 6.33|-.59|16#
#Pair 1pc - pnc#10.57| 13.69| 3.32| 3.53|17.61|3.18|16#
#==============#=====#==============#===============#======#=====#====#==#
2.3(2:2) T-TEST. Paired Samples Test
#===============#
# #
# #
# #
# #
#Sig. (2-tailed)#
#===============#
# .57#
# 1.99#
#===============#
3.1 T-TEST. Paired Sample Statistics
#==========#======#==#==============#========#
# # Mean | N|Std. Deviation|SE. Mean#
#==========#======#==#==============#========#
#Pair 0 dc #370.20|17| 68.85| 16.70#
# dnc#372.61|17| 75.13| 18.22#
#Pair 1 pc #376.36|17| 66.92| 16.23#
# pnc#365.79|17| 65.10| 15.79#
#==========#======#==#==============#========#
3.2 T-TEST. Paired Samples Correlations
#======#========#==#===========#====#
# | # N|Correlation|Sig.#
#======#========#==#===========#====#
#Pair 0|dc & dnc#17| .98| .00#
#Pair 1|pc & pnc#17| .98| .00#
#======#========#==#===========#====#
3.3(1) T-TEST. Paired Samples Test
#==============#=================================================#====#==#
# # Paired Differences | | #
# #-----+--------------+---------------+------------+ | #
# # | | | 95% | | #
# # | | +------+-----+ | #
# # Mean|Std. Deviation|Std. Error Mean| Lower|Upper| t |df#
#==============#=====#==============#===============#======#=====#====#==#
#Pair 0dc - dnc#-2.41| 17.01| 4.12|-11.16| 6.33|-.59|16#
#Pair 1pc - pnc#10.57| 13.69| 3.32| 3.53|17.61|3.18|16#
#==============#=====#==============#===============#======#=====#====#==#
3.3(2:2) T-TEST. Paired Samples Test
#===============#
# #
# #
# #
# #
#Sig. (2-tailed)#
#===============#
# .57#
# 1.99#******************** p-value > 1.0!! SPSS gives 0.006
#===============#
Please let me know what's going on here. Is it just a numerical problem
with
very small p-values??
Cheers
Bill
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