Question

Difficulty: MediumDescriptive Statistics and Data Representations

During a science experiment, a student measured the temperature changes of a liquid in degrees Celsius at seven different intervals. The recorded changes were 15C15^\circ\text{C}, 6C6^\circ\text{C}, 20C20^\circ\text{C}, 24C24^\circ\text{C}, 7C7^\circ\text{C}, 4C4^\circ\text{C}, and 8C8^\circ\text{C}. What is the positive difference between the median and the mean of these seven recorded temperatures?

  1. 4Answer
  2. B
    6
  3. C
    8
  4. D
    12
  5. E
    16

Answer

4
To find the correct positive difference, we first find the mean by dividing the sum of the temperatures by 7: (15+6+20+24+7+4+8)/7=84/7=12(15 + 6 + 20 + 24 + 7 + 4 + 8) / 7 = 84 / 7 = 12. We then sort the temperatures in ascending order: 4,6,7,8,15,20,244, 6, 7, 8, 15, 20, 24. The median is the middle value of this sorted list, which is 8. The positive difference between the median and the mean is 812=4|8 - 12| = 4.

Step-by-Step Solution

1
Calculate the mean of the temperatures.
Mean = 12
Sum the seven values (15+6+20+24+7+4+8=8415 + 6 + 20 + 24 + 7 + 4 + 8 = 84) and divide by the total number of data points (7) to get 84/7=1284 / 7 = 12.
2
Find the median of the temperatures.
Median = 8
Sort the values in ascending order: 4,6,7,8,15,20,244, 6, 7, 8, 15, 20, 24. Since there are 7 data points, the median is the fourth value, which is 8.
3
Calculate the positive difference between the median and the mean.
Positive difference = 4
Subtract the median from the mean (or vice versa) and take the absolute value: 812=4|8 - 12| = 4.

Key Concept

Calculating and comparing the mean and median of a dataset, including the necessity of sorting data before finding the median.
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