Question

Maester wear a chain around their necks composed of various metals to signify their personal expertise. Maesters personally forge each link themselves. Each link indicates a different field of study. There are sixteen recognized fields each with a different representative metal. However, it decades of study to earn these links. Based on the distribution presented below, what is the expected number of metals on a Maester's chain.

probability 0.25 0.15 0.4 0.2

number of links 7 9 12 16

Answer 1

Answer

Expected value = sum of individual number of links by respective probability

using the probability distribution given in the question

this implies

E[x] = (7*0.25) +(9*0.15)+(12*0.4)+(16*0.2)

= 1.75 + 1.35 + 4.8 + 3.2

= 11.1

Expected number of metals on a Maester's chain is 11.1