We now have enough data to calculate the first moving range.

Module | A6 | A5 | ||||||
---|---|---|---|---|---|---|---|---|

Date Completed | 20/8 | 21/8 | ||||||

Actual | 33.0 | 37.5 | ||||||

Estimated | 37.5 | 30.0 | ||||||

X | -4.5 | 7.5 | ||||||

mR |

Remember that the moving range is just like the range for a subgroup of size 2. To calculate it we need to subtract the smaller X value from the greater:

mR = 7.5 - -4.5

Or because the two negatives combine to make a positive, we could say:

mR = 7.5 + 4.5

So what is the first moving range?