题目
The student's t distribution is a function of
选项
A.Normal distribution
B.Chi-square distribution
C.Lognormal distribution
D.Normal and chi-square distributions
答案
D
解析
Normal and chi-square distributions. The t-distribution (also known as the Student t-distribution) occurs again as a function of other random variables, namely the normal and the Chi-square distribution. If X is a standard normal random variable and Z a Chi-square distributed random variable with n degrees of freedom which is independent of X, then by definition the distribution of the random variable Y defined as Y = X/√(Z/n) possesses a t-distribution with n degrees of freedom.” 正态分布和卡方分布。 t分布（也称为学生t分布）根据其他随机变量（即正态分布和卡方分布）再次出现。 如果X是标准正态随机变量，Z是独立于X的具有n个自由度的卡方分布随机变量，则根据定义，随机变量Y的分布定义为Y = X/√(Z/n)，拥有n个自由度的t分布。