Sometimes, no comparisons will be made at all. We will assume data represent a simple random sample taken from a defined population. We also assume that measurements are of good quality. Without such assumptions, inferences would be baseless. To illustrate techniques in this chapter, we consider a data set representing body weights of diabetics.
Body weight is expressed as a percentage of ideal.
We should report the mean, standard deviation, and sample size. Although Epi Info reports summary statistics to three decimal places, you should report fewer. The sample mean is the point estimator of expected value . We want to test whether the sample mean differs significantly from expected value 0 . The value of expected value 0 can be based on an established norm or some other theoretical consideration.