Answer:
The ratio of blue marbles to red marbles is 35:15. To test his hypothesis in the best way, he should make sure that the total number of marbles he draws is 100. In other words, both sides of the ratio added together should equal 100. Right now, both sides equal 50 (35 + 15 = 50). To get to 100, double both sides of the ratio. Now, the ratio is 70:30. Based on the 50 marbles Sam drew, there are 70 blue marbles and 30 red marbles, meaning Sam's hypothesis is incorrect, and there are more blue marbles than red.