The video tutorial explains the concept of normal distribution using an IQ test as an example. It covers the mean, median, and mode, which are equal in a normal distribution, and explains how to calculate standard deviations and z-scores. The tutorial also demonstrates how to determine the percentage of data within certain ranges of the distribution, using specific examples and calculations. Advanced calculations are discussed to deepen understanding of the distribution's properties.

What is the central value around which a normal distribution is centered?

• The mode

• The median

• The range

• The mean

How many standard deviations are typically marked on either side of the mean in a normal distribution?

• One

• Two

• Three

• Four

What does a Z-score of zero indicate?

• The value is below the mean

• The value is above the mean

• The value is at the median

• The value is at the mean

What percentage of the population lies within one standard deviation of the mean in a normal distribution?

• 68%

• 50%

• 95%

• 99.7%

What percentage of the population lies within three standard deviations of the mean?

• 68%

• 95%

• 100%

• 99.7%

What is the Z-score range for values within three standard deviations of the mean?

• 0 to 3

• -2 to 2

• -1 to 1

• -3 to 3

What is the percentage of the population that lies above a Z-score of 2?

• 13.5%

• 2.5%

• 34%

• 5%

If 68% of the population is within one standard deviation, what percentage is outside this range?

• 32%

• 2%

• 16%

• 5%

What is the percentage of the population that lies above an IQ score of 130?

• 5%

• 34%

• 2.5%

• 13.5%

What is the total percentage of the population that lies within two standard deviations of the mean?

• 95%

• 100%

• 68%

• 99.7%