The lengths of human pregnancies are normally distributed with a mean of 268 days and a standard deviation of 16 days. What is the probability that a pregnancy lasts less than 280 days? 0.2266 0.7734 0.0179 0.4443 0.9821

To find the probability that a pregnancy lasts less than 280 days, we first need to standardize the value using the Z-score formula: \[ Z = \frac{(X - \mu)}{\sigma} \] where \( X \) is the pregnancy length (280 days), \( \mu \) is the mean (268 days), and \( \sigma \) is the standard deviation (16 days). Calculating the Z-score: \[ Z = \frac{(280 - 268)}{16} = \frac{12}{16} = 0.75 \] Now, we can look up the Z-score of 0.75 in the standard normal distribution table or use a calculator. The area to the left of Z=0.75 is approximately 0.7734. So, the probability that a pregnancy lasts less than 280 days is approximately 0.7734. Now you can choose methods of doubling your fun with probability! This probability tells us that nearly 77.34% of pregnancies last less than 280 days, a fairly reassuring number when you're in the waiting game! However, remember that every pregnancy is unique; those extra few days might produce the most surprising results!