The owners of shaving ice are concerned that many of their customers are starting to purchase their icy treats from cold as ice because of its new shaved-ice syrup, which has fewer grams of sugar than shaving ice. a random sample of 100 strawberry shaved ices from shaving ice found a mean of 22 grams of sugar and a standard deviation of 3.2 grams. a random sample of 100 strawberry shaved ices from cold as ice found a mean of 18 grams of sugar and a standard deviation of 2.1 grams. which of the following formulas gives a 99% confidence interval for the difference in mean grams of sugar between a shaving ice strawberry shaved ice and a cold as ice strawberry shaved ice?
a. 4 + 2.63 √(3.2/100 + 2.1/100)
b. 4 + 2.63 √(3.2²/99 + 2.1²/99)
c. 4 + 2.576 √(3.2²/99 + 2.1²/99)
d. 4 + 2.63 √(3.2²/100 + 2.1²/100)
e. 4 + 2.576 √(3.2²/100 + 2.1²/100)