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# Statistics Concepts: Cases and Observations

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14. Approximately ______ of the area (cases or observations) under the
normal curve is found between 1 standard deviation above and 1 standard deviation below the mean.

15. What percentage of area (or cases or observations) is found above a z value of 1.96? ._____

16. A random sample of 20 observations is drawn from a population with a standard deviation of 677. Calculate the standard error of the mean.

17. Under what condition do you calculate the t statistic?

18. Under what condition do you calculate the z statistic?

19. Define Type I error. (2 Points) Define Type II error:

23. A _____________ table is a classification tool that reveals the various possibilities in the comparison of two variables.

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#### Solution Preview

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14. Approximately ______ of the area (cases or observations) under the
normal curve is found between 1 standard deviation above and 1 standard deviation below the mean. (2 Points)

You can use z-table to find P(Z<-1)=P(Z>1)=0.1587.

15. What percentage of area (or cases or observations) is found above a z value of 1.96? ._____ (2 Points)

The ...

#### Solution Summary

This solution considers statistics concepts.

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