In an activity, students are pulling marbles from a large jar containing blue and red marbles. In their sample, students will calculate the proportion of red marbles. Which of the following sample sizes will have the smallest sampling variability?

Larger samples tend to produce less variable estimates of a population proportion. Among the choices, 40 is the largest sample size, so the proportion of red marbles calculated from samples of 40 will have the smallest sampling variability.

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