At a large, rural high school, 21% of sophomores have an allergy to ragweed, while 17% of seniors have one. Let p hat Subscript Upper F and P hat Subscript s be the sample proportions of sophomores and seniors, respectively, who have an allergy to ragweed. Suppose 50 sophomores and 62 seniors from this school are selected at random and asked if they have an allergy to ragweed. Which of the following is the correct calculation and interpretation of the standard deviation of the sampling distribution of p hat Subscript Upper F Baseline minus p hat Subscript s ?

The difference (sophomores – seniors) in the sample proportions of those who have an allergy to ragweed typically varies about 0.001 from the true difference in proportions.
The difference (sophomores – seniors) in the sample proportions of those who have an allergy to ragweed typically varies about 0.006 from the true difference in proportions.
The difference (sophomores – seniors) in the sample proportions of those who have an allergy to ragweed typically varies about 0.032 from the true difference in proportions.
The difference (sophomores – seniors) in the sample proportions of those who have an allergy to ragweed typically varies about 0.075 from the true difference in proportions.