7 In Marumbo, three quarters of the adults own a cell phone.
- A random sample of 8 adults from Marumbo is taken. Find the probability that the number of adults who own a cell phone is between 4 and 6 inclusive.
- A random sample of 160 adults from Marumbo is taken. Use an approximation to find the probability that more than 114 of them own a cell phone.
- Justify the use of your approximation in part (ii).