T-Test results with Null Values

[Lost_Gary]

I am performing proc ttest and attempting to compare the equal and unequal variances.  Some of my unequal variances are missing.  I assume that this is because of very small observations within the sample (such as only 1).  My question is how do I interpret this within the ttest procedure.  Should i refer to the equal variances or consider these to small to calculate?  

Thanks

[Reeza]

Too small to calculate

[PaigeMiller]

I have a different opinion. The fact that you have only one data point for some level of the category variable in the t-test does not mean that the variances are too small to calculate. It means that the variances cannot be calculated.

[Reeza]

Variances don't exist for an N=1 🙂

[PaigeMiller]

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@Reeza wrote:
Variances don't exist for an N=1 🙂

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Population variances do exist, but you can't estimate them with the sample of 1.