7 A pair of fair coins is thrown repeatedly until a pair of tails is obtained. The number of throws taken is denoted by the random variable \(X\).
- State the expected value of \(X\).
- Find the probability that exactly 3 throws are required to obtain a pair of tails.
- Find the probability that fewer than 4 throws are required to obtain a pair of tails.
- Find the least integer \(N\) such that the probability of obtaining a pair of tails in fewer than \(N\) throws is more than 0.95 .