निम्नलिखित में से किसे अपकिरण (dispersion) का सापेक्ष माप माना जाता है?

Read the following statements about measures of central tendency and dispersion, and identify the correct statements: A. Mean deviation is always calculated from the mode only. B. The value of mean deviation does not take into account all the individual observations of the dataset. C. Variance is defined as the arithmetic mean of the squared deviations from the arithmetic mean. D. Variance is a widely used descriptive and algebraic measure of dispersion. Choose the correct answer from the options given below:

Read the following statements about classical linear regression based on the ordinary least squares (OLS) method and identify the correct statements: A. The sum of the vertical deviations of the observed values from the estimated straight line is equal to zero. B. It is not possible to estimate the dependent variable using linear regression equations. C. The variable to be predicted or estimated is called the dependent variable. D. The sum of the squares of vertical deviations of the observed values from the derived straight line is minimized. Choose the correct answer from the options given below: