Question

statistics help anyone? http://prntscr.com/2rdzus

Answer 1

a)
The variance of this uniform random distribution is (n^2 - 1)/12, here have n = 200 so variance is (200^2 - 1)/12 = 13333/4. The variance is the square root of this, giving us approximately, 57.7. So we would expect the number of 4's to be
$$
0.1 * 200 \pm 57.7
$$
Which gives us a range of 0 to 77 about 68 percent of the time. So finding only 4 4's is well within expectations.

Note that the larger the number of samples, the wider the variance.

b)

You would expect to find 0.1*1000 7's in a table of 1000 numbers. Of course, there will be some variance as discussed above.