# Doubt regarding Normality Testing

Six Sigma – iSixSigma Forums Old Forums General Doubt regarding Normality Testing

Viewing 6 posts - 1 through 6 (of 6 total)
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• #44035

sai
Member

Could someone help me to clear my query. For normality testing, what hypothesis we should set for null and alternative?
Regards,
Sai

0
#140457

indresh
Participant

Always remember this
When P is high Null Should Fly
In normality test Null Hypothesis is that the data is normal
High p value we accept Null hypothesis
rgds

0
#140458

sai
Member

Dear Indresh,
But null is what we are stuck with and alternative is what we want to prove it. Generally we would like our data to be normal to perform many tools, then how come null will be data is normal.
Regards,
Sai

0
#140459

indresh
Participant

Yes we would like to proceed with normal data and null hypothesis shall be that the data is normal
So whats the issue, did’nt quite get what you mean by your statement

0
#140461

indresh
Participant

A null hypothesis (H0) is a stated assumption that there is no difference in parameters (mean, variance, DPMO) for two or more populations.
Classic definition from this site itself
i hope this makes things clear
in cases where we wanna find out if there exist an relation between y and x , null would be no there does not hence less the p value we take that relationship exists. similarily if we are to find out is there any difference between these two populations etc null is that there is no difference and higher the p value higher the probability that there actually exist no relation or chances of there existing a relation is less.
hope this helps
rgds

0
#140463

sai
Member

So if i am checking for normality through Minitab and if i get p-value of 0.567, it shows that your are accepting your data to be normal with such a greater risk. Am i right in this decision?