PLS HELP GIVING BRAINLESS TO CORRECT PERSON PLS HELP ASAP

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?

If t17 = 3 (t5) in an arithmetic progression, find t1 in terms of d.

What is the measure of sty in oo below? 130 310 230 50