Question

determine the actual class intervals of the distribution if mean and SD are given​

Answer 1

Answer:

The Text I am reading has a question that goes like this :

Explain clearly the ideas implied in using arbitrary working origin and scale for the calculation of arithmetic mean and standard deviation of a frequency distribution. The values of the arithmetic mean and standard deviation of the following frequency distribution of a continuous variable derived from the analysis in the above manner are 40.604lb and 7.92lb. Determine the actual class intervals.

x: −3 −2 −1 0 1 2 3 4 f: 3 15 45 57 50 36 25 9

Please correct me if I am wrong, I think that the change in scale and origin would be required if some of the meaningless values have to be removed from the distribution, like in the distribution above the unit we are considering is lb which is related to weight and hence values −3,−2,−1,0 are problematic. Hence, the transformation yi=5−xi would make all the values greater than equal to one, but still what about the class intervals ?