PLEASE HELP ME I'LL MARK BRAINLIEST I KNOW THE ANSWER ISN'T 2/6

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?

Simplify -4z+2y-y+-18z a.-22z+y b.-14z+2 c.3y+22z d.y +14z

When you flip a biased coin the probability of getting a tail is 0.6. how many times would you expect to get tails if you flip the coin 320 times?