Skewness (Edexcel GCSE Statistics): Flashcards
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Describe positive skew in data distribution.
Describe positive skew in data distribution.
Data clusters left, tail extends right, mean > median > mode.
State the formula used to calculate skewness numerically.
State the formula used to calculate skewness numerically.
Skew = 3(Mean - Median) / Standard deviation.
What does a skewness value of 0 indicate?
What does a skewness value of 0 indicate?
Perfectly symmetrical distribution.
In the worked example, what type of skewness was identified?
In the worked example, what type of skewness was identified?
Positive skewness, since median closer to lower quartile.
How does the mean relate to skewness in positive skew?
How does the mean relate to skewness in positive skew?
Mean > Median > Mode, mean pulled right.
What does a skewness value of -1.2 suggest?
What does a skewness value of -1.2 suggest?
A significant negative skew.
Determine skew from LQ=4, median=6, UQ=12
Determine skew from LQ=4, median=6, UQ=12
Positive skew, median closer to LQ (right tail)
If mean > median > mode, what is skew?
If mean > median > mode, what is skew?
Positive skew (tail to the right)
Boxplot: median-LQ=5, UQ-median=2. State skew
Boxplot: median-LQ=5, UQ-median=2. State skew
Negative skew (median nearer UQ, left tail)
Find skewness and type using mean 7.6, median 6, sd 5.54
Find skewness and type using mean 7.6, median 6, sd 5.54
Skew ~ 0.87; positive skew (mean > median > mode)