I have a set of 18 observations. Three of the observations have a score of over 97 and are associated with a positive response, to which I assign the value of 1.

The remaining 15 observations have scores that are less than 96 and are associated with a negative response, to which I assign the value of 0.

I would like to have R calculate a statistically significant cutoff value associated with a “p value”.

My questions:

What type of data structure do I place my data into?

How do I instruct R to calculate the cutoff value?

What “library” or “package” does R use to calculate the cutoff value?

Do I choose a “p value” or does R calculate it?

Thanks in advance for your help.

Jim