Explain briefly what is meant by a random sample.
Random numbers are used to select, with replacement, a sample of size \(n\) from a population numbered 000, 001, 002, ..., 799.
If \(n = 6\), find the probability that exactly 4 of the selected sample have numbers less than 500 .
If \(n = 60\), use a suitable approximation to calculate the probability that at least 40 of the selected sample have numbers less than 500 .