Write each ratio as a fraction in simplest form. then explain its meaning. 4 flutes and two drums

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?

A. 127 cm^2 b. 144.5 cm^2 c. 172 cm^2 d. 50 cm^2

What is the upper quartile in the box plot?