Comparing Populations Using Mean Absolute Deviation

The video tutorial explains how to use the Mean Absolute Deviation (MAD) to compare two populations. It begins with a review of calculating the mean, followed by a detailed process of finding the MAD for boys' and girls' spending data. The tutorial highlights the importance of understanding deviations and variance, emphasizing that variance numbers are always positive. It concludes with a comparison of the boys' and girls' data, demonstrating that the boys' mean is more useful due to a smaller MAD. The lesson teaches how to determine the relevance of the mean using MAD.

What is the first step in finding the mean of a data set?

• Divide the sum by the number of addends

• Multiply all the numbers together

• Find the sum of all the addends

• Subtract the smallest number from the largest

How do you calculate the mean absolute deviation?

• Multiply the mean by the number of data points

• Find the difference between the largest and smallest data points

• Subtract the mean from each data point and sum the results

• Add all deviations and divide by the number of data points

Why are variance numbers always positive?

• Because they are calculated using only positive numbers

• Because they are squared values

• Because negative numbers are not allowed in statistics

• Because they represent absolute values

What was the mean amount spent by the girls?

• 235

• 824

• 185

• 206

Which group had a smaller mean absolute deviation?

• The boys

• The girls

• Neither had a deviation

• Both had the same

What does a large mean absolute deviation indicate about the mean?

• The mean is not relevant

• The data points are all the same

• The data is very consistent

• The mean is very useful

In comparing the boys' and girls' spending, what was the most obvious difference?

• The boys' spending was more varied

• The boys spent more money

• The girls spent more money

• Both spent the same amount