A company has discovered that a recent batch of batteries had manufacturing flaws, and has issued a recall. In a group of 15 batteries covered by the recall, 6 are dead. Two batteries at random are chosen from the package of 15.
a) Has the assumption of independence been met? Explain.
b) Create a probability model for the number of good batteries chosen.
c) What's the expected number of good batteries?
d) What's the standard deviation?