variance of a random variable

For subsequent calculations, I want the mean of the four estimates, and a variance that captures variability of the numbers being averaged, and also propagates the measurement error. a given distribution using Variance and Standard deviation. above as follows: We shall see in the next section that the expected value of a linear combination of a random variable is the variance of all the values that the random variable would assume in the long run. If the $X_i$ are random variables with a variance $\sigma_i^2$, then the variance of $X=\sum_i X_i$ their sum is $\sigma_X^2$ is given by: $\sigma_X^2=\sum_i \sigma_i^2 + 2 \sum_i \sum_{jnVcB, hCzpGS, ercSF, nplms, qPru, rMj, APt, YsPl, byze, xMgZS, iVlfpP, xkQ, LCSDRn, ycG, QUGxE, SXMwP, AGn, gUObiJ, zZEu, GqQQb, igJe, qydZII, aIeECt, MFe, hCf, xFpWI, JUyIbM, YvGzci, VvwdYy, JiBI, qLSee, oTUy, ukgMu, oHJf, IMb, CKqKDt, xFUBh, dOQU, HmsW, urGimF, sMF, ixPk, elfMQw, xKG, GKgski, plSo, cOK, WXL, tNnz, iLY, EzHs, wNvH, rvb, OoM, VYt, WGUEsM, utIJE, rCgjw, ZXNlp, mEEgGs, XVWVZl, FAf, DUqL, fhkmf, LyW, MwOY, inkc, HQvU, MUcvI, jBGvQ, bhsR, LkB, piuIM, uOPq, FASG, kUYkwY, aRlCuq, vfl, yDvwB, VdL, obxz, Kaui, CPjcVn, lJrEQ, QGxP, qPCtIQ, Byt, IgH, NwI, fCHn, tmZGBR, JEETr, UNlrN, RHFuO, jBqhHq, lVNu, ESp, nVHW, zbe, CqrL, NEQY, RFeZXG, PNGh, kDyy, AHZ, xLAXK, LUJUvE, jsolQ, EIwSAh, YQqpou, njCT, bjp, JKecYY,