Please help me with theses questions, step by step. Thank you..

Q1. A coin was tossed 12 times and probability of getting head is .5

A) what is the probability of at least 11 heads in 12 tosses?

B) Find the mean, Variance, and standard for this binomial probability distribution.

Q2. The heights of a pediatrician's three year old females are normally distributed with a mean of 38.72 inches and standard deviation of 3.17 inches. Find the height of a 3 year old female that separates the bottom 20% from the top 80%.

Q3. According to the higher education research institute, 55% of college freshmen in 4 year colleges and universities during 2003 were females. Suppose 12 freshmen are randomly selected and the numbers of females are recorded. Find the probability that not more than 8 are females.

Q4. An airline estimates that only 85% of the people booked on their flights actually show up. if the airline books 16 people on a flight with a maximum capacity of 14, what is the probability that the flight will be overbooked? Is it unusual for 15 people to show up for the flight? explain.