What is the slope of the line

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?

Which equation can be used to measure the density of water in a spherical water tank? let w represent the number of water particles within the region.

Suppose that 15 inches of wire cost 60 cents. at the same rate, how much (in cents) will 12 inches of wire cost