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Statistical calculation of individuals with astigmatism

See attached file.

Table 2.12 Distribution of astigmatism in 1033 young men age 18-22

Degree of astigmatism (diopters) Frequency

0.0 or less than 0.2 458
0.2 - 0.3 268
0.4 - 0.5 151
0.6 - 0.1 79
1.1 - 2.0 44
2.1- 3.0 19
3.1- 4.0 9
4.1- 5.0 3
5.1- 6.0 2
1033

Table 2.12 comes from the paper giving the distribution of astigmatism in 1033 young men ranging in age from 18 to 22 who were accepted for military service in Great Britain. Assume that astigmatism is rounded to the nearest 10th of the diopter and each subject in a group has the average astigmatism within that group (e.g., for the group 0.2- 0.3 diopters, the actual range is from 0.15 to 0.35 diopters), and assume that each man in the group has an astigmatism of (0.15 + 0.35)/2=0.25 diopters.

2.8) compute the arithmetic mean.
2.9) compute the standard deviation.

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Please see the attached Excel sheet for an explicit example of this calculation. You may look at each cell to see the calculation preformed in that cell.

This is a very simple question of descriptive statistics. The arithmetic mean is simply the average of all your values which can be ...

Solution Summary

Distribution of astigmatism in 1033 young men: Compute the arithmetic mean and the standard deviation

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