• The average life of a bread-making machine is 8 years, with a standard deviation of 2. Assuming that the lives of these machines follow approximately a normal distribution, find • The probability...

Extracted text: • The average life of a bread-making machine is 8 years, with a standard deviation of 2. Assuming that the lives of these machines follow approximately a normal distribution, find • The probability that the mean life of a random sample of 11 such machines falls between 7.2 and 8.4 years. • The value of k to the right of which 20% of the means computed from random samples of size 11 would fall.