Construct the sampling distribution of the sample proportion of heads, for flipping a balanced coin (a) Once. (b) Twice. (Hint: The possible samples are (H, H), (H, T), (T, H), (T, T).) (c) Three times. (Hint: There are 8 possible samples.) (d) Four times. (Hint: There are 16 possible samples.) (e) Describe how the shape of the sampling distribution seems to be changing as the number of flips increases.