Let d be the set of positive divisors of 12, ordered by divisibility, and let e be the set of even positive divisors of 12, ordered by divisibility.

a. (a) is d a boolean algebra? explain. you may appeal to facts from section 13.4.

b. (b) is e a boolean algebra? explain. do not appeal to facts from section 13.4

3.17 scores on stats final. below are final exam scores of 20 introductory statistics students. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 57, 66, 69, 71, 72, 73, 74, 77, 78, 78, 79, 79, 81, 81, 82, 83, 83, 88, 89, 94 (a) the mean score is 77.7 points. with a standard deviation of 8.44 points. use this information to determine if the scores approximately follow the 68-95-99.7% rule. (b) do these data appear to follow a normal distribution? explain your reasoning using the graphs provided below.

The owner of the plant nursery where you were tells you to fill 350 ml bottles from a 30 l from a fertilizer

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )