Question

A sample data set has a mean of 61.1 and a standard deviation of 7.8. Fine the minimum and maximum "usual" values of the data set
1)51.3 and 70.9
2)45.5 and 76.7
3)53.3 and 68.9
4)37.7 and 84.5

Answers

GPT-4o mini
In statistics, "usual" values are often defined as those that fall within ±2 standard deviations from the mean.

Given:
- Mean (\( \mu \)) = 61.1
- Standard deviation (\( \sigma \)) = 7.8

To find the minimum and maximum usual values:
1. Calculate \( \mu - 2\sigma \) for the minimum usual value:
\[
61.1 - 2(7.8) = 61.1 - 15.6 = 45.5
\]

2. Calculate \( \mu + 2\sigma \) for the maximum usual value:
\[
61.1 + 2(7.8) = 61.1 + 15.6 = 76.7
\]

Thus, the minimum and maximum usual values are 45.5 and 76.7, respectively.

The correct answer is:
**2) 45.5 and 76.7**.

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