Which measure should be used to describe the dispersion of the skewed distribution. ()
A. range
B. arithmetic mean
CV
D. inter-quartile range
E. median
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There is a normal distribution x~N(0, 100), what is the standard deviation:()
A. 0
B. 10
C. 100
D. 10000
E. 1
How much is the area of the normal distribution from μ-1.64σ to μ+1.64σ? ()
A. 95%
B. 90%
C. 97.5%
D. 47.5%
E. 45%
The degree of freedom in χ2 test for 2×2 table is:()
A. 0
B. n
C. n-1
D. 1
E. 4
To compare the difference of the mean among three populations, which of the following methods should be used?()
A. t test
B. z test
C. ANOVA
D. chi-square test
E. Wilcoxon rank sun test