Can we predict next sample using the existing samples? Suppose that I have 18 data points and I'm sampling 3 data points each time. Suppose that I have 60 samples (each has 3 data points). Can we predict the next sample (of 3 points) from the existing sample? or the most recent sample?

Sure - you could use the mean of the samples you've taken or something. 
Anything can be used as a prediction, but without any additional information, you can't say how good the prediction will be. 
