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Q.3770 What are the conventional values of skewness and kurtosis of a normal random variable?
A
Skewness=0, kurtosis=3
B
Skewness=1, kurtosis=3
C
Skewness=0, kurtosis=2
D
Skewness=0, kurtosis=4
Explanation:
In a normal distribution:
Choice B is incorrect: Skewness of 1 implies significant asymmetry, which contradicts the symmetric property of a normal distribution.
Choice C is incorrect: Kurtosis of 2 indicates lighter tails and fewer outliers than the normal distribution, which is not characteristic of a normal random variable.
Choice D is incorrect: While higher kurtosis can indicate fat tails, for a standard normal random variable, the total kurtosis should be 3, not 4. Excess kurtosis (kurtosis above that of the normal distribution) should be zero.
Therefore, the conventional values of skewness and kurtosis for a normal random variable are 0 and 3, respectively.