QUESTION IMAGE
Question
the movement of the progress bar may be uneven because questions can be worth more or less (including zero) depending on your answer. which of the following statements about the box - and - whisker plot below is not true? the midrange of the data set shown is between 80 and 82. both 72 and 99 are values in the set of data. there are the same number of data points in the upper two quartiles and the two lower quartiles. the midrange of the data set shown is 85.5.
To solve this, we analyze each option using box - and - whisker plot concepts:
Step 1: Recall key concepts
- Midrange: It is calculated as $\frac{\text{minimum}+\text{maximum}}{2}$.
- Quartiles: A box - and - whisker plot divides data into four quartiles, each containing approximately 25% of the data points.
- Whiskers: They represent the range of the data (excluding outliers), with the left whisker starting at the minimum value and the right whisker ending at the maximum value.
Step 2: Analyze Option A
From the plot, the minimum value (left whisker start) is 72 and the maximum value (right whisker end) is 99. The midrange is $\frac{72 + 99}{2}=\frac{171}{2}=85.5$. 85.5 is between 80 and 82? No, 85.5 is between 85 and 86. Wait, maybe we misread the minimum and maximum. Wait, looking at the number line: the left whisker starts at 72 (the first vertical line on the left whisker) and the right whisker ends at 99 (the last vertical line on the right whisker). Wait, no, let's check the number line again. The leftmost point of the left whisker is at 72, and the rightmost point of the right whisker is at 99. Then midrange is $\frac{72 + 99}{2}=85.5$. 85.5 is not between 80 and 82. But wait, maybe we made a mistake. Wait, let's check other options first.
Step 3: Analyze Option B
In a box - and - whisker plot, the whiskers extend to the minimum and maximum values of the data set (excluding outliers). The left whisker starts at 72, so 72 is a data point (the minimum). The right whisker ends at 99, so 99 is a data point (the maximum). So this statement is true.
Step 4: Analyze Option C
By the definition of a box - and - whisker plot, each quartile contains approximately 25% of the data. So the upper two quartiles (the two quartiles above the median) and the lower two quartiles (the two quartiles below the median) each contain 50% of the data points. So the number of data points in the upper two quartiles and the lower two quartiles is the same. This statement is true.
Step 5: Analyze Option D
As calculated before, midrange $=\frac{72 + 99}{2}=\frac{171}{2}=85.5$. This statement is true.
Now, going back to Option A. The midrange is 85.5, which is not between 80 and 82. But wait, maybe we misidentified the minimum and maximum. Wait, looking at the number line: the left whisker starts at 72 (the first mark on the left whisker) and the right whisker ends at 99 (the last mark on the right whisker). So the minimum is 72, maximum is 99. Midrange is 85.5. So Option A says "The midrange of the data set shown is between 80 and 82" which is false. But wait, the question is which statement is not true. Wait, maybe we made a mistake. Wait, let's re - evaluate Option A. Wait, maybe the minimum is 72 and maximum is 99, midrange is 85.5. 85.5 is not between 80 and 82. But let's check the other options again.
Wait, Option B: "Both 72 and 99 are values in the set of data." In a box - and - whisker plot, the ends of the whiskers represent the minimum and maximum values of the data set (assuming no outliers). So the left whisker starts at 72, so 72 is the minimum, and the right whisker ends at 99, so 99 is the maximum. So 72 and 99 are in the data set. So this is true.
Option C: "There are the same number of data points in the upper two quartiles and the two lower quartiles." Since the box - and - whisker plot divides the data into four quartiles, each with approximately 25% of the data. So the lower two quartiles (first and second) contain 50% of the data, and the upper two quartiles (third and fourth) contain 50% of the da…
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The midrange of the data set shown is between 80 and 82.