DataBSc

### Questions (7)

 4 Why isn't standard deviation $\frac{1}{n}\sqrt{\sum^n_{i=1}(x_i - \mu)^2}$? 2 How are probability functions derived? E.g. normal, Poisson, t-distribution 2 Why is $\frac{\sum^n_{i=1}(X_i-\bar{X})^2}{\sigma^2}$chi-square distributed with $n-1$ degrees of freedom? 2 Deriving likelihood function of binomial distribution, confusion over exponents 2 In hypothesis testing, why is $1-\beta$ called the “power of a test”?

### Reputation (229)

 +20 How are probability functions derived? E.g. normal, Poisson, t-distribution +40 Why isn't standard deviation $\frac{1}{n}\sqrt{\sum^n_{i=1}(x_i - \mu)^2}$? +20 Why is $\frac{\sum^n_{i=1}(X_i-\bar{X})^2}{\sigma^2}$chi-square distributed with $n-1$ degrees of freedom? +10 In hypothesis testing, why is $1-\beta$ called the “power of a test”?

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### Tags (22)

 0 hypothesis-testing × 2 0 point-estimation 0 maximum-likelihood 0 p-value 0 likelihood 0 statistical-significance 0 estimation 0 wilcoxon-signed-rank 0 binomial 0 chi-squared