Question 96:

Asked on March 1, 2008

Tags: Z-Score

1

Answer:

No answer provided yet.

We can compute a z-score using the x value of 53.  The z-score is calcualted as a data-point minus the mean and that result divided by the standard deviation. That gets us (53-60)/4 = -1.75 (notice the negative value).

Now we need to look up the area in a standard normal curve. We want the area that is less than 1.75 standard deviations below the mean (this is what a -1.75 z-score means). We can use a z-table or the z-score to percentile calculator. Select 1-sided area. We want the sliver of area that is less than 1.75, which is .040059 or 4%. So the probability x is less than 53 is 4%.