Many samples, many means

You will write functions that take random samples from a small made-up population of travel times and collect their means. The checker tests each function.

The idea. One sample gives one mean. Many samples give many means, and their pattern is the sampling distribution. Its centre is close to the population mean, and its spread is smaller than the spread of the population.

Your tasks.

1. Finish sample_mean(values, n). Take random.sample(values, n) and return its mean.
2. Finish many_means(values, n, repeats). Return a list of repeats sample means.
3. Finish share_within(means, centre, distance). Return the share of the means that lie within distance of centre.