Evan Weaver, the lead engineer in Twitter’s services team, reports that the population of Twitter users has an average of 126 followers. Assume the standard deviation in this population is 30 followers. You plan to draw a sample of 225 Twitter users.

a. What is the probability that the average number of followers for the sample will be less than 120?

b. It is approximately 68.3% likely that the sample average will be between 124 and _____ followers.

c. What is the probability that the average number of followers for the sample will be within 2.58 standard deviations (that is, ±2.58σx) of the average number of followers for the full population of Twitter users?