The exponential function y = 3(4)x grows by a factor of 4 between x = 1 and x = 2. What factor does it grow by between x = 3 and x = 4
A) 3
B) 4
C) 12
D) 576

Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.1. (round your answers to four decimal places.) (a) if the distribution is normal, what is the probability that the sample mean hardness for a random sample of 8 pins is at least 51?