5. Which of the following statements related to data treatment is (are) correct?(AB) The mean of a data set is found by adding all numbers in the data set and then dividing by the number of values in the set.(AC) The variance is the square root of the standard deviation.(AD) The standard error of the mean is the standard deviation of the mean.(AE) The coefficient of variation is the percent relative standard deviation.(BC) The standard error of the mean of 5 measurements is larger than the standard deviation of a single result.(BD) As the desired confidence level decreases, the confidence interval increases.