For the next six month period sammy wants to calculate the monthly deviation from the average.    month    sales        average    deviationjuly        $1,750      1,460.83    [                ]aug        $1,800      1,460.83    [                  ]sept.      $1,6251,    1,460.83  [                ]oct.      $1,395        1,460.83        -65.83nov.      $1, 2151    1,460.83    [                ]dec.        $980        1,460.83    [                ]

Deviation:

July 289.17

August 339.17

September 14800.17

October -65.83

November 10690.17

December -480.83

The details are shown below.  When sales is less than average we get negative sign.

Step-by-step explanation:

Month    sales       Average   Deviation

July       $1,750     1,460.83   [      290.17          ]

Aug       $1,800     1,460.83   [    340 .17           ]

Sept.     $1,6251,   1,460.83  [      164 .27         ]

Oct.      $1,395       1,460.83       -65.83

Nov.      $1, 2151    1,460.83   [       -245.73        ]

Dec.       $980        1,460.83    [               ]