Question

The mean clotting time of blood is 7.45 seconds with a standard deviation of 3.6 seconds. what is the probability that an​ individual's clotting time will be less than 3 seconds or greater than 13 ​seconds? assume a normal distribution. this problem can be solved using technology or the table for the standard normal curve from your text.

Answer 1

Less than 3 is about 10.75% and greater than 13 is about 6.18%.

To find these percents, you need to find the z-score for each value. Then, use your table to find the correct percent. Be sure to find the side above 13 when you use your chart.

For less than 3:
(3 - 7.45) / 3.6 = -1.24 = The percent below this is 0.1075

For greater than 13:
(13 - 7.45) / 3.6 = 1.54 = The percent above this is 0.0618