A random sample of 100 foxes was examined by a team of veterinarians to determine the prevalence of a particular type of parasite. Counting the number of parasites per fox, the veterinarians found that 65 foxes had no parasites, 20 had one parasite, and so on. A frequency tabulation of the data is given here:
Number of Parasites, x 0 1 2 3 4 5 6 7 8
Number of Foxes, f 65 20 7 3 1 2 1 0 1
(1) Calculate the sample mean for the sample.
(2) Calculate the sample variance for the following sample (advanced level question).