I have some samples from eight people who all gave the same answer to a question. Now, obviously the sample's mean is the answer all people gave, and the standard dev is 0. Excel throws a
#NUM! error when I call the function
CONFIDENCE.T(0.05, K33, COUNTA(B33:I33))
K33 is the standard dev (0).
What would be the correct interpretation of this? Can I even calculate a confidence interval?
For clarification: People are asked to give their opinion on a scale of (1, 2, 3, 4, 5), which is ordinal. Nevertheless, one always calculates the arithmetic mean of all judgements (according to ITU-T P.800, see also: Wikipedia), so that's why I also want to get a confidence interval.