Question

a sample data set has a mean of 122.3 and a standard deviation of 18.5. convert a score of 168.4 to a z score and determine if the score is \usual\ or \unusual.\ (1 point) 1.23; usual -1.23; usual 2.49; unusual -2.49; unusual

Explanation:

Step1: Calculate the z - score

The formula for the z - score is \(z=\frac{x-\mu}{\sigma}\), where \(x = 168.4\), \(\mu=122.3\), and \(\sigma = 18.5\).

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Step2: Determine if the score is usual or unusual

A z - score is considered unusual if \(|z|> 2\). Since \(z = 2.49>2\), the score is unusual.

Answer:

C. 2.49; unusual