Question 7  Use the following information to answer Question 7 and Question 8. The marks of six students in a Mathematics test are represented by the variable x. The following data was  produced: n=6, Σx = 279 and Σx2 = 13 093. Find the mean and standard deviation of the following data. A. mean =46.5 , standard deviation = 5.82 B. mean = 52.5, standard deviation = 4.89 C. mean =46.5 , standard deviation = 4.89 D. mean =52.5 , standard deviation = 5.82 Question 8  It was later discovered that one of the values was incorrectly recorded as 43. The correct value,  in fact, is 34. Find the new values of the mean and standard deviation. A. mean = 45 , standard deviation = 7.07 B. mean = 51, standard deviation = 6.84 C. mean = 45 , standard deviation = 6.84 D. mean = 51 , standard deviation = 7.07

Definition Definition Measure of central tendency that is the average of a given data set. The mean value is evaluated as the quotient of the sum of all observations by the sample size. The mean, in contrast to a median, is affected by extreme values. Very large or very small values can distract the mean from the center of the data. Arithmetic mean: The most common type of mean is the arithmetic mean. It is evaluated using the formula: μ = 1 N ∑ i = 1 N x i Other types of means are the geometric mean, logarithmic mean, and harmonic mean. Geometric mean: The nth root of the product of n observations from a data set is defined as the geometric mean of the set: G = x 1 x 2 ... x n n Logarithmic mean: The difference of the natural logarithms of the two numbers, divided by the difference between the numbers is the logarithmic mean of the two numbers. The logarithmic mean is used particularly in heat transfer and mass transfer. ln x 2 − ln x 1 x 2 − x 1 Harmonic mean: The inverse of the arithmetic mean of the inverses of all the numbers in a data set is the harmonic mean of the data. 1 1 x 1 + 1 x 2 + ...