| Question : If a distribution of test scores is normal with a mean of 78 and a standard deviation of 11, what percent of the area lies below 60 Answer : Calculate the z-score by subtracting the data-point from the mean and dividing that result by the standard deviation. So (60-78)/11 = -1.636. Then to find the area, enter -1.636 into the z-score to percentile calculator and select one sided area. You should get around 5%. You can also visually see that z-score by looking at the interactive graph of the standard normal curve and hovering over a z-score of -1.636 for the 1-sided curve. By the way, a negative z-score tells you that the area is less than 50%. | How helpful was this answer?
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