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Z Score & Percentile

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See Attached- need to see if #1 is correct, unsure of how to start # 2.

1. A set of 50 data values has a mean of 15 and a variance of 25. Find the standard score of a data value = 30.

2. A research study of manual dexterity involved determining the time required to complete a task. The time required for each of 40 individuals with disabilities is shown here (data are ranked):

7.1 7.2 7.2 7.6 7.6 7.9 8.1 8.1 8.1 8.3 8.3 8.4 8.4 8.9
9.0 9.0 9.1 9.1 9.1 9.1 9.4 9.6 9.9 10.1 10.1 10.1 10.2
10.3 10.5 10.7 11.0 11.1 11.2 11.2 11.2 12.0 13.6 14.7 14.9 15.5

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The solution provides step by step method for the calculation of z score and percentile. Formula for the calculation is also included.

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1. A set of 50 data values has a mean of 15 and a variance of 25. Find the standard score of a data value = 30.

Answer

Given that µ = 15, σ2 = 25, X = ...

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