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Learning Math Home
Data Session 9, Part D: The Effect of Sample Size
 
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Session 9, Part D:
The Effect of Sample Size (30 minutes)

In This Part: Sample Size 20 | Comparing Sample Sizes 10 and 20 | Box Plot Comparisons

All of our estimates thus far have been based on a sample size of 10 randomly selected sub-regions out of 100. In this part, we will examine the effects of changing the sample size to 20 sub-regions.

Here is a sequence of 20 random numbers selected by sampling without replacement:

81 48 66 94 87 60 51 30 92 97 00 41 27 12 38 64 93 79 50 59

Here is the corresponding sample of 20 sub-regions:

As before, we estimate the total number of penguins in the region by finding the mean of our samples, and then multiplying by 100 (the number of regions):

100 x [(5 + 6 + 5 + 6 + 3 + 7 + 4 + 5 + 5 + 7 + 5 + 5 + 4 + 4 + 5 + 6 + 7 + 4 + 5 + 4)/20] = 510

This estimate is very accurate (it is within 10 of the actual number of penguins). Let's now investigate the effect that increasing the sample size has on the accuracy of our estimation procedure.


Next > Part D (Continued): Comparing Sample Sizes 10 and 20

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