2.10 · Part II
Supported Application · Guided Entry to Today's Problem
Appropriate Measures of Center · Mean
- Symmetric Data (No Outliers): Use Mean and MAD
- Skewed Data (Has Outliers): Use Median and IQR (outliers distort the mean)
- Compare distributions using both center (typical value) and spread (variability)
- Appropriate Measures of Center (Medidas de centro apropiadas) — A mean, median, or mode chosen because it describes a data set fairly.
- Mean (Media) — The average. Add all the numbers, then divide by how many there are.
- Median (Mediana) — The middle number when you put them in order.
- Outlier (Valor atípico) — A number that is much bigger or smaller than the rest.
- Skewed (Sesgado) — When most data sits on one side with a tail on the other.
- Data distribution (Distribución de datos) — How the data looks: where it sits and how spread out it is.
- A common mistake in Appropriate Measures is defaulting to the mean just because "it uses all the data," without first checking whether an outlier or skewed shape is present. For example, given a player's points per game 14, 16, 15, 17, 16, 58, a student calculates the mean (136 ÷ 6 ≈ 22.7) and reports that as the typical game — but 58 is far from the cluster of 14–17, so it pulls the mean above 5 of the 6 games. The median (16) actually represents a typical game here. Before choosing a measure, always scan the data for an outlier or a long tail first: only use the mean once you've confirmed the data has neither.
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1 MATCHING
Match each data description with the best measure of center.
- Test scores: 88, 90, 85, 92, 87 (no outliers)
- Salaries: $30K, $32K, $35K, $31K, $250K
- Race times: 12.1s, 12.3s, 12.0s, 12.2s, 12.1s
- Goals scored: 1, 2, 1, 0, 2, 1, 15
- AMean
- BMedian
- CMean
- DMedian
Writing Task: Justify why your mathematical solution is accurate and complete.
2.10 · Part II
On-Level Application · Standard Rigor
Appropriate Measures of Center · Mean
- Symmetric Data (No Outliers): Use Mean and MAD
- Skewed Data (Has Outliers): Use Median and IQR (outliers distort the mean)
- Compare distributions using both center (typical value) and spread (variability)
- Appropriate Measures of Center (Medidas de centro apropiadas) — A mean, median, or mode chosen because it describes a data set fairly.
- Mean (Media) — The average. Add all the numbers, then divide by how many there are.
- Median (Mediana) — The middle number when you put them in order.
- Outlier (Valor atípico) — A number that is much bigger or smaller than the rest.
- Skewed (Sesgado) — When most data sits on one side with a tail on the other.
- Data distribution (Distribución de datos) — How the data looks: where it sits and how spread out it is.
- A common mistake in Appropriate Measures is defaulting to the mean just because "it uses all the data," without first checking whether an outlier or skewed shape is present. For example, given a player's points per game 14, 16, 15, 17, 16, 58, a student calculates the mean (136 ÷ 6 ≈ 22.7) and reports that as the typical game — but 58 is far from the cluster of 14–17, so it pulls the mean above 5 of the 6 games. The median (16) actually represents a typical game here. Before choosing a measure, always scan the data for an outlier or a long tail first: only use the mean once you've confirmed the data has neither.
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1 MATCHING
Match the reason with whether to use mean or median.
- Data is symmetric and has no extreme values
- Data has one or more outliers
- Data is skewed to one side
- All values are clustered close together
- AUse Mean
- BUse Median
- CUse Median
- DUse Mean
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2 MULTIPLE CHOICE
A baseball player's batting averages over 6 seasons are: .280, .295, .290, .285, .300, .110. The .110 was an injury-shortened season. Which measure better represents the player's typical batting average?
- AMedian, because the .110 outlier pulls the mean down
- BMean, because it uses all the data
- CMean, because .110 is a real season
- DNeither measure works
✏️ Workspace & Solution Steps -
3 MULTIPLE CHOICE
A scout records points per game: 14, 16, 15, 17, 16, 58. To report a TYPICAL game, which measure of center is best?
- AMedian, because 58 is an outlier that pulls the mean up
- BMean, because it uses every game
- CRange, because it shows the highest game
- DMode, because 16 appears twice
✏️ Workspace & Solution Steps
Writing Task: Justify why your mathematical solution is accurate and complete.
2.10 · Part II
Extension & Non-Routine Application
Appropriate Measures of Center · Mean
- Symmetric Data (No Outliers): Use Mean and MAD
- Skewed Data (Has Outliers): Use Median and IQR (outliers distort the mean)
- Compare distributions using both center (typical value) and spread (variability)
- Appropriate Measures of Center (Medidas de centro apropiadas) — A mean, median, or mode chosen because it describes a data set fairly.
- Mean (Media) — The average. Add all the numbers, then divide by how many there are.
- Median (Mediana) — The middle number when you put them in order.
- Outlier (Valor atípico) — A number that is much bigger or smaller than the rest.
- Skewed (Sesgado) — When most data sits on one side with a tail on the other.
- Data distribution (Distribución de datos) — How the data looks: where it sits and how spread out it is.
- A common mistake in Appropriate Measures is defaulting to the mean just because "it uses all the data," without first checking whether an outlier or skewed shape is present. For example, given a player's points per game 14, 16, 15, 17, 16, 58, a student calculates the mean (136 ÷ 6 ≈ 22.7) and reports that as the typical game — but 58 is far from the cluster of 14–17, so it pulls the mean above 5 of the 6 games. The median (16) actually represents a typical game here. Before choosing a measure, always scan the data for an outlier or a long tail first: only use the mean once you've confirmed the data has neither.
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1 MULTIPLE CHOICE
A data set of house prices contains one mansion worth far more than every other home. Which pair of measures best describes this data?
- AMedian and IQR
- BMean and MAD
- CMean and range
- DMode and range
✏️ Workspace & Solution Steps
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2 OPEN RESPONSE
A local newspaper reports that the average home price in a neighborhood is $450,000. The actual prices are: $180K, $200K, $190K, $210K, $195K, $1,725K. Is the reporter's claim misleading? Calculate the mean and median and explain which better represents a 'typical' home price.
✏️ Mathematical Justification & Response
Writing Task: Justify why your mathematical solution is accurate and complete.