The lengths of pregnancies in a small rural village are normally distributed with a mean of 261 days and a standard deviation of 13 days. A distribution of values is normal with a mean of 261 and a standard deviation of 13. What percentage of pregnancies last fewer than 251 days? P(X < 251 days) - % Enter your answer as a percent accurate to 1 decimal place (do not enter the "%" sign). Answers obtained using exact z-scores or z-scores rounded to 3 decimal places are accepted.

IQ scores are normally distributed with a mean of 100 and a standard deviation of 15.  What is the minimum IQ required to be able to correctly claim to be in the "top 5%" of IQ scores. Round to the nearest whole number.

A distribution of values is normal with a mean of 116.2 and a standard deviation of 60.1. Find P43, which is the score separating the bottom 43% from the top 57%. P43 = Enter your answer as a number accurate to 4 decimal places.

The IRS claims it takes an average of 3.7 hours to complete a 1040 tax form. Assume the time t the form is normally distributed with a standard deviation of 15 minutes or 0.25 hours. complete Use the Cumulative Z-Score Table to answer the following questions. Write your answer as a percent using 2 decimal places. What percent of people would you expect to complete the form in less than 3.45 hours? What percent of people would you expect to complete the form-in more than 3.45 hours? What percent of people would you expect to complete the form in less than 3.4 hours? What percent of people would you expect to complete the form in more than 3.4 hours? What percent of people would you expect to complete the form between 3.4 and 3.45 hours?

z Scores LeBron James, one of the most successful basketball players of all time, has a height of 6 feet 8 inches, or 203 cm. Based on statistics from Data Set 1 “Body Data” in Appendix B, his height converts to the z score of 4.07. How many standard deviations is his height above the mean?

Listen According to Chebyshev's theorem, for a data set with a mean of 100 and a standard deviation of 5, which interval is guaranteed to contain at least 88.89% of the data set?

A distribution of values is normal with a mean of 246.2 and a standard deviation of 99.5. Find P78, which is the score separating the bottom 78% from the top 22%. P78 Enter your answer as a number accurate to 4 decimal places.