Understanding Normal Distribution and the Empirical Rule

The video tutorial explains the concept of normal distribution using exam completion times as an example. It covers the calculation of mean and standard deviation, and applies the empirical rule to determine the percentage of data within one, two, and three standard deviations from the mean. The tutorial provides a step-by-step guide to calculating these values and understanding their significance in the context of a bell curve.

What is the mean time to complete the exam?

• 55 minutes

• 39 minutes

• 31 minutes

• 47 minutes

What is the standard deviation of the exam completion times?

• 6 minutes

• 7 minutes

• 8 minutes

• 9 minutes

What is the time range for one standard deviation from the mean?

• 15 to 63 minutes

• 23 to 55 minutes

• 31 to 47 minutes

• 39 to 47 minutes

According to the empirical rule, what percentage of data falls within one standard deviation of the mean?

• 95%

• 50%

• 68%

• 99.7%

What is the upper limit of two standard deviations from the mean?

• 63 minutes

• 39 minutes

• 55 minutes

• 47 minutes

What is the lower limit of two standard deviations from the mean?

• 39 minutes

• 15 minutes

• 31 minutes

• 23 minutes

What percentage of data falls within two standard deviations of the mean according to the empirical rule?

• 68%

• 50%

• 95%

• 99.7%

What is the upper limit of three standard deviations from the mean?

• 39 minutes

• 63 minutes

• 55 minutes

• 47 minutes

What is the lower limit of three standard deviations from the mean?

• 31 minutes

• 23 minutes

• 15 minutes

• 39 minutes

According to the empirical rule, what percentage of data falls within three standard deviations of the mean?

• 99.7%

• 68%

• 50%

• 95%