normality
Six Sigma – iSixSigma › Forums › Old Forums › General › normality
- This topic has 7 replies, 5 voices, and was last updated 15 years ago by
Tierradentro.
-
AuthorPosts
-
August 13, 2007 at 11:10 am #47812
KatrinaParticipant@KatrinaInclude @Katrina in your post and this person will
be notified via email.hey, what is the reasoning for the a value >0.05 to signify normality?! Why has this value been chosen as the cut off point?!
thanks
kat0August 13, 2007 at 11:57 am #159861http://www.sportsci.org/resource/stats/pvalues.html
Just take a look at it,Hope it answers your query.
Cheers0August 13, 2007 at 12:21 pm #159865
KatrinaParticipant@KatrinaInclude @Katrina in your post and this person will
be notified via email.hey, thanks for your reply, hopefully will understand it once ive had a proper read
cheers kat0August 13, 2007 at 2:47 pm #159873
KatrinaParticipant@KatrinaInclude @Katrina in your post and this person will
be notified via email.hey, Ive read that article and im still not clear as to why a >0.05 value would signify that the data is normal?! why this value?!
thanks
kat0August 13, 2007 at 4:51 pm #159880
Jim ShelorParticipant@Jim-ShelorInclude @Jim-Shelor in your post and this person will
be notified via email.Katrina,
The value 0.05 comes from the confidence level you want for your answer. If you want a confidence level of 95%, then if P<0.05, you reject the null hypothesis because the p is significant.
In this case, the null hypothesis is the distribution is normal. Therefore, a p<0.05 says to reject the null. Accordingly, the distribution is not normal.
If for this case, null hypothesis = distribution normal, your p>0.05, there is insufficient evidence to show the null is not true at the 95% confidence level and you fail to reject the null hypothesis. Your distribution is normal.
You can use a 90% confidence level, in which case the significant p level is 0.1; or a 99% confidence level in which case your significant p level is 0.01 (1-confidence).
I hope this helps.
Respects,
Jim Shelor0August 13, 2007 at 5:28 pm #159885Kat:The number is based on this statement from R.A. Fisher (1890-1962) on whether something that occurs is due to random chance or otherwise. It was pretty arbitrary, but everyone has come to agree to the 1 in 20 rule.… either there is something in the treatment, or a coincidence has occurred such as does not occur in 1 in 20 trials (Journal of the Ministry of Agriculture of Great Britain, 1926)Cheers, BTDT
0August 14, 2007 at 9:47 am #159905
KatrinaParticipant@KatrinaInclude @Katrina in your post and this person will
be notified via email.thanks for your help guys, think i get it now, was over complicating things lol!
cheers
kat0August 14, 2007 at 11:27 am #159907
TierradentroParticipant@johnInclude @john in your post and this person will
be notified via email.I used to wonder about this too…. thanks for the question and the answer
John
Business Consultant
http://www.pralayass.com0 -
AuthorPosts
The forum ‘General’ is closed to new topics and replies.