Medical billing errors and fraud are on the rise. According to one​ study, 4 out of 5 ​times, the medical bills received by patients are not right. Using binomial distribution and rounding to the...

Medical billing errors and fraud are on the rise. According to one​ study, 4 out of 5 ​times, the medical bills received by patients are not right. Using binomial distribution and rounding to the fourth,

1. If a sample of 11 medical bills is selected, what is the probability that MORE than 7 bills contain errors?

2. What are the mean and standard deviation of the probability distribution?