A local realty office sells on average 10 houses a week. Let X measure the number of houses they will sell in the next week. Determine
  1. the probability the realty office sells 12 houses next week.
  2. the probability the realty office sells fewer than 10 houses next week.
  3. the interval \(\mu - 2\sigma \le X \le \mu + 2\sigma\text{.}\)
  4. \(P(\mu - 2\sigma \le X \le \mu + 2\sigma)\text{.}\)