A random sample of 100 rods from a population line were measured and found to have a mean length of XXXXXXXXXXwith standard deviation 0.11. A further sample of 50 is taken. Find the probability that...

A random sample of 100 rods from a population line were measured and found to have a mean length of 12.132 with standard deviation 0.11. A further sample of 50 is taken. Find the probability that the mean of this sample will be between 12.12 and 12.14.

A random sample of 20 children in a large school were asked a question and 12 answered correctly. Estimate the proportion of children in the school who answered correctly and the standard error of this estimate.