Coin tosses in a large class of introductory statistics students, the professor has each student toss a coin 16 times and calculate the proportion of his or her tosses that were heads. the students then report their results, and the professor plots a histogram of these several proportions. a. what shape would you expect this histogram to be? why? b. where do you expect the histogram to be centered? c. how much variability would you expect among these proportions? d. explain why a normal model should not be used here.

(50 ) mrs. julien’s and mrs. castillejo’s classes are selling cookie dough for a school fundraiser. customers can buy packages of macadamia nut chip cookie dough and packages of triple chocolate cookie dough. mrs. julien’s class sold 25 packages of macadamia nut chip cookie dough and 30 packages of triple chocolate cookie dough for a total of $221.25. mrs. castillejo’s class sold 5 packages of macadamia nut chip cookie dough and 45 packages of triple chocolate cookie dough for a total of $191.25. (a) write the system of equations that model the problem. be sure to explain which equation represents which situation. (b) find the cost of each type of cookie. show your work. (c) explain which method you used to solve the system and why you chose that method.