Proof that $\sum_{i=1}^{n}e_i X_i = 0$ in simple linear regression
20216
Why do residuals in linear regression always sum to zero when an intercept is included?
141370
Linear Regression of Indicator Matrix: sum of predictions is 1
11942
show that $x$ is in $\ell^1$ if $\sum x_ny_n$ is convergent for all $y=(y_n)\in{c_0}$
22129
Why is $\sqrt{\sum_{i=1}^n |v_i|^2} \leq \sum_{i=1}^n |v_i|$ true?
67452
Prove sum of unindependent Gaussian random variable is still Gaussian
146333
Gaussian proof for the sum of squares?
147111
Where is the Proof for the Sum-to-Product rule derrived from?
9665
Proof of the independence of the sample mean and sample variance
104258
Proof Verification: $\dim\mathrm{Im} T+\dim\ker T=\dim V$
85626
prove $\sum_{i=1}^{n}(x_i-\bar{x})^2\lt\sum_{i=1}^{n}(x_i-a)^2$
27901
Proving $\sum\limits_{i=1}^k | \langle x,v_i \rangle \langle y,v_i\rangle| \leq \|x\|\cdot \|y\|$
96119
Derive Variance of regression coefficient in simple linear regression
67106
Projection on the hyperplane $H: \sum x_i=0$
127047
How to show that $\sum_{i=1}^n | \langle f, f_i\rangle |^2 \leq \Vert f \Vert^2$
7448
Prove $S \doteq \sum_{n=1}^{\infty} p_n  0$ assuming $0 \leq p_n < 1$.
67454
Show that $\sum_{i=1}^n (x_i - \bar{x})(y_i - \bar{y}) = \sum_{i=1}^n (x_i - \bar{x})(y_i)$.
122562
Cross product term in linear regression why is it zero