A box contained 1,500 marbles; 600 were red and the others, blue. the fol - lowing procedure was repeated many times. one hundred draws were made at random with replacement from the box; the number of red marbles among the draws was counted. the first 10 counts were 38, 35, 37, 31, 36, 39, 36, 33, 30, 34. is anything fishy? answer yes or no, and explain.

Question

Mathematics

Eden Gibson

12 December, 18:42

A box contained 1,500 marbles; 600 were red and the others, blue. the fol - lowing procedure was repeated many times. one hundred draws were made at random with replacement from the box; the number of red marbles among the draws was counted. the first 10 counts were 38, 35, 37, 31, 36, 39, 36, 33, 30, 34. is anything fishy? answer yes or no, and explain.

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Answers (1)

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Izabelle Morales · Answer 1

Step-by-step explanation:

The theoretical probability of drawing a red marble is 600/1500

= 2/5 or 40%

So in a draw of 100 you would expect about 40 red marbles to be drawn.

The average of th first 10 counts is 35 which is 5 lower than the expected value.

I would say there is something fishy with this as they are consistently below the 40.