In 2016, it was reported that 6% of all first-time mothers were 19 years old. Suppose a sample of 400 new mothers is chosen.

Find the proportion of a sample of 400 first-time mothers that are 19 years old below which 60% of all proportions of samples of 400 first-time mothers that are 19 years old fall.

Find the proportions of a sample of 400 first-time mothers that are 19 years old between which the middle 85% of all proportions of samples of 400 first-time mothers that are 19 years old fall