PLASSS HELP

a. 9
b. 81
c. 3
d. 24

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?

What is the x-intercept and y-intercept of the equation 2x+1. 2o

Out of 50 students surveyed, 16 have a dog. based on these results, predict how many of the 280 students in the school have a dog.