Kurtosis Formula:
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Kurtosis is a statistical measure that describes the degree to which a probability distribution is concentrated around its mean versus in its tails. It measures the "tailedness" of the distribution relative to a normal distribution.
The calculator uses the kurtosis formula:
Where:
Explanation: The formula calculates the fourth standardized moment about the mean, normalized by the standard deviation raised to the fourth power.
Details: Kurtosis helps identify whether data exhibits heavy tails or light tails compared to a normal distribution. High kurtosis indicates heavy tails and more outliers, while low kurtosis indicates light tails and fewer outliers.
Tips: Enter numerical values separated by commas. The calculator will compute the mean, standard deviation, and kurtosis of your dataset. Ensure you have at least 4 data points for meaningful results.
Q1: What does kurtosis tell us about a distribution?
A: Kurtosis measures the tailedness of a distribution. High kurtosis means heavy tails and more extreme values, while low kurtosis means light tails and fewer extremes.
Q2: What is the kurtosis of a normal distribution?
A: A normal distribution has a kurtosis of 3. Many statistical packages report excess kurtosis (kurtosis - 3), where 0 indicates normal tail behavior.
Q3: What are the types of kurtosis?
A: Mesokurtic (kurtosis = 3, normal), Leptokurtic (kurtosis > 3, heavy-tailed), Platykurtic (kurtosis < 3, light-tailed).
Q4: When is kurtosis most useful?
A: Kurtosis is particularly important in risk management, finance, and quality control where extreme values (outliers) have significant consequences.
Q5: Are there limitations to kurtosis?
A: Kurtosis can be sensitive to sample size and may not fully capture distribution shape. It should be used alongside other descriptive statistics like skewness.