Math Problem Statement
explain how D is correct
Solution
To explain why option D is correct, let's break down the key concepts and the histogram provided.
Key Terms:
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Mean: The average value of a dataset.
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Median: The middle value of a dataset when it is ordered.
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Skewness: Refers to the asymmetry in the distribution of data.
- Skewed to the left (negative skewness): The tail on the left side is longer. In such distributions, the mean is less than the median.
- Skewed to the right (positive skewness): The tail on the right side is longer. Here, the mean is typically greater than the median.
Understanding the Histogram:
The histogram in the question shows estimated monthly salaries of company employees based on their years of experience. From the graph:
- The bar for the "19–21 years" group is much higher than the others.
- The salary distribution shows that most employees with more experience (19–21 years) earn significantly higher salaries.
However, there is no long tail to the right of this higher salary range (meaning that the distribution is not right-skewed). Instead, the graph suggests more employees have lower salaries with fewer years of experience, while only a few earn much higher salaries.
This results in a left-skewed (or negatively skewed) distribution because:
- The bulk of the data (heights of bars) is concentrated on the right side, with a tail (lower salaries) extending to the left.
Correct Answer (D):
- Since the data is skewed to the left, the mean will be less than the median.
- This is reflected in option D, which states: "The mean is likely less than the median because the data is skewed to the left."
Why the Other Options are Incorrect:
- B (your answer) mentions that the data is skewed to the right, which is incorrect based on the histogram.
- A also mentions right skewness, which is incorrect.
- C states the data is skewed to the left but incorrectly concludes that the mean is greater than the median, which contradicts the typical behavior of left-skewed distributions.
Would you like more details on skewness, or any other part of this explanation?
Related Questions:
- How do you calculate mean and median from a dataset?
- What are the key differences between left-skewed and right-skewed distributions?
- Can you explain how outliers affect mean and median differently?
- How does the shape of a histogram help in identifying skewness?
- How would the distribution change if the higher salaries (rightmost bar) were more frequent?
Tip:
In left-skewed distributions, the long tail pulls the mean lower, so it tends to be less than the median.
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Math Problem Analysis
Mathematical Concepts
Statistics
Data Analysis
Skewness
Mean and Median
Formulas
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Theorems
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Suitable Grade Level
Grades 9-12
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