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The outcome of each of 30 items was observed: 10 items gave an outcome 1/2 - d each, 10 items gave an outcome 1/2 each and the remaining 10 items gave outcome 1/2 + d each. If the variance of this outcome data is 4/3 then |d| equals:
- 2/3
- √5/2
- √2
- 2
Correct answer: √2
Solution
The variance is calculated based on the squared differences from the mean. Given the outcomes and their frequencies, the calculations lead to the conclusion that |d| must equal √2 to satisfy the variance condition of 4/3.
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