Let x be a random variable that represents the amount of a r

Let x be a random variable that represents the amount of a randomly selected monthly cell phone bill. We know that x has a normal distribution with a mean of

Solution

x score lies between 62 and 65

Convert them into z scores.

z scores are -1.50/2.68 and 1.5/2.68

= -0.5560,+0.5560

Required probability = Prob of |Z|<0.5560 = 0.4246