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Decide if each situation is true or false. Explain your reasoning.
The mean of the data in the dot plot is 4.
The median of the data in the dot plot is 3.5.
The heart rates of eight high school students are listed in beats per minute:
Calculate the MAD using the same data from the previous activity by finding the average distance from each data value to the mean. You may find it helpful to organize your work by completing the table provided.
| data values | mean | deviation from the mean (data value - mean) |
absolute deviation |deviation| |
|---|---|---|---|
| 72 | |||
| 75 | |||
| 81 | |||
| 76 | |||
| 76 | |||
| 77 | |||
| 79 | |||
| 78 |
MAD:
For another data set, all of the values are either 3 beats per minute above the mean or 3 beats per minute below the mean. Is that enough information to find the MAD for this data set? If so, find the MAD. If not, what other information is needed? Explain your reasoning.
Several pennies are placed along a meter stick, and the position in centimeters of each penny is recorded. The mean position is the 50 centimeter mark and the MAD is 10 centimeters. What information does this tell you about the position of the pennies along the meter stick?
The mean absolute deviation, or MAD, and the interquartile range, or IQR, are measures of variability. Measures of variability tell you how much the values in a data set tend to differ from one another. A greater measure of variability means that the data are more spread out, while a smaller measure of variability means that the data are more consistent and are closer to the measure of center.
To calculate the MAD of a data set:
|data value – mean|
To calculate the IQR, subtract the value of the first quartile from the value of the third quartile. Recall that the first and third quartile are included in the five-number summary.