Using HP 12c or HP 12c Platinum for Cost Estimation with Linear Regression

Johnson’s Chair Company has experienced the following costs for the first 6 months of the year:
# Chairs Made 5,000 5,500 4,800 5,300 4,950 5,150	Total Costs $120,000 $122,100 $118,540 $122,400 $119,100 $124,200

Entering data in HP 12c:

• [f] [REG]
• 120,000 [ENTER] 5,000 [Σ+]
• 122,100 [ENTER] 5,500 [Σ+]
• 118,540 [ENTER] 4,800 [Σ+]
• 122,400 [ENTER] 5,300 [Σ+]
• 119,100 [ENTER] 4,950 [Σ+]
• 124,200 [ENTER] 5,150 [Σ+]

Johnson’s fixed cost (Even when no chair was build):

• Press 0 then [g] [y,m]
• Display 89,449.381 is the Answer

Johnson’s variable cost (cost of a single chair):

• Press 1 then [g] [y,m]
• Display 89,455.559
• Deduct this with the above fixed cost 89,449.381
• 6.178 which is the cost for one unit of chair.

How good is the fit of the linear regression line generated?

• Press 0 then [g] [y,m]
• Press 1 then [Shift] [y,m]
• Press [x<>y]
• Display 0.716 this is the answer

Total costs for 5,400 chairs:

• Enter 5,400 then press [g] [y,m]
• Display 122,806.907 is the Answer.

Total costs were $125,000, how many chairs:

• Enter 125,000 then press  [g] [x,m]
• Display 5,755.023 is the Answer.