What is the zvalue associated with a 25 alpha risk The answe

What is the z-value associated with a 2.5% alpha risk?

The answer is 2.24, but I\'m not sure how to get there. And is a Z chart used?

Solution

1 - 2.5% = a proportion of .025 2 - Using the Standard Normal Table, look in Column C for .025, then take the value in Column A. This is the Z score (-1.95996). It is negative since on the left side of the distribution. 3 - Convert the Z score to a raw score. Y = 70.07 + -1.95996 (10.27) = 49.94121 4 - 49.941 is the raw score that bounds the lower 2.5% of the distribution. The Z score associated with 49.941 in this distribution is -1.95996