Using HP 17bII+ 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 17bII+:

• [Shift] [CLR DATA]
• Press top soft key {SUM}
• 5,000 [INPUT]
• 5,500 [INPUT]
• 4,800 [INPUT]
• 5,300 [INPUT]
• 4,950 [INPUT]
• 5,150 [INPUT]
• [EXIT]
• Press top soft key {NAME}
• Press top soft key {ABCDE}{C}
• Press top soft key {FGHI}{H}
• Press top soft key {FGHI}{I}
• Press top soft key {RSTUV}{R}
• Press top soft key {RSTUV}{S}
• [INPUT]
• Press top soft key {GET}{*NEW}
• 120,000 [INPUT]
• 122,100 [INPUT]
• 118,540 [INPUT]
• 122,400 [INPUT]
• 119,100 [INPUT]
• 124,200 [INPUT]
• [EXIT]
• Press top soft key {NAME}
• Press top soft key {RSTUV}{T}
• Press top soft key {ABCDE}{C}
• [INPUT]
•  

Johnson’s fixed cost:

• Press [SHIFT][MAIN]
• Press top soft key {SUM} {CALC} {MORE} {FRCST}
• Prompted "Select X Variable"
• Press top soft key {CHAIRS}
• Prompted "Select Y Variable"
• Press top soft key {TC}
• Displayed "LINEAR"
• Press top soft key {B} is Y intersect, this is fixed cost - when no chair was build.{M} is the unit cost
• Display 89,449.381 is the Answer

Johnson’s variable cost:

• Press top soft key  {M}
• Display 6.178 which is the cost for one unit of chair.

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

• Press top soft key {CORR} Display 0.716 this is the answer

Total costs for 5,400 chairs:

• Enter 5,400 then press {CHAIRS}
• Display 122,806.907 is the Answer.

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

• Enter 125,000 then press {TC}
• Display 5,755.023 is the Answer.

This solution is also applicable to HP 17bII and HP 19bII Financial Calculator.