Understanding Normal Distribution and the Empirical Rule

The video tutorial explains the concept of normal distribution, focusing on the mean and standard deviation. It demonstrates how to calculate intervals using sigma and applies the empirical rule to determine the percentage of data within one, two, and three standard deviations from the mean. The tutorial also clarifies the relationship between the mean, median, and mode in a normal distribution, emphasizing that they are all located at the center of the distribution.

What is the mean time to complete the exam?

• 37 minutes

• 35 minutes

• 39 minutes

• 41 minutes

What is the standard deviation of the exam completion times?

• 1.5 minutes

• 2.1 minutes

• 2.5 minutes

• 3.0 minutes

What is the value of mu plus two sigma?

• 43.3

• 45.4

• 41.2

• 39.1

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

• 99.7%

• 95%

• 68%

• 50%

What is the range of times that includes approximately 68% of the testing times?

• 37 to 39.1 minutes

• 30.7 to 43.3 minutes

• 34.9 to 39.1 minutes

• 32.8 to 41.2 minutes

What percentage of data falls within two standard deviations of the mean?

• 99.7%

• 68%

• 75%

• 95%

What is the range of times that includes approximately 95% of the testing times?

• 34.9 to 39.1 minutes

• 37 to 39.1 minutes

• 32.8 to 41.2 minutes

• 30.7 to 43.3 minutes

What percentage of data falls within three standard deviations of the mean?

• 68%

• 95%

• 99.7%

• 100%

What is the range of times that includes approximately 99.7% of the testing times?

• 32.8 to 41.2 minutes

• 34.9 to 39.1 minutes

• 30.7 to 43.3 minutes

• 37 to 39.1 minutes

In a normal distribution, what percentage of testing times are below the mean?

• 25%

• 50%

• 75%

• 100%