The average number of Xerox copies made in a working day in a certain office is 356 with a standard deviation of 55. It costs the firm three pence per copy. During a working period of 121 days what is...

The average number of Xerox copies made in a working day in a certain office is 356 with a standard deviation of 55. It costs the firm three pence per copy. During a working period of 121 days what is the probability that the average cost per day is more than £11.10?

A random sample of 5 values was taken from a population: 8.1, 6.5, 4.9, 7.3, and 5.9. Estimate the population mean and standard deviation, and the standard error of the estimate for the population mean.