Complete the following steps to specify the response and the expectation function.

- In Response, enter the column of numeric data that you want to explain or predict. The response is also called the Y variable.
- In Expectation Function, enter the function that describes the relationship between the predictors and the expected response value using one of the following methods:
- Use Catalog: Click to choose a predefined function. For more information, see the section on Use catalog.
- Use Calculator: Click to use the calculator to enter a custom function. For more information, see the section on Use calculator.
- Edit directly: Enter the function directly into the text box.

In this worksheet, Expansion is the response variable. Kelvin is the predictor variable and appears in the expectation function. The expectation function that describes the relationship between the response and predictor is (Theta1+Theta2*Kelvin+Theta3*Kelvin^2+Theta4*Kelvin^3)/(1+Theta5*Kelvin+Theta6*Kelvin^2+Theta7*Kelvin^3).

C1 | C2 |
---|---|

Expansion | Kelvin |

0.591 | 24.41 |

1.547 | 34.82 |

2.902 | 44.09 |

2.894 | 45.07 |

Select a predefined expectation function.

- Show functions
- Select a category to filter the list of functions. You can narrow down the functions to make it easier to find the one you want.
- Function
- Select an expectation function. You can select a function that is supplied by Minitab or a custom function that you have previously entered. Minitab automatically adds a custom function to the catalog when you first use it to perform a nonlinear regression analysis. After you choose a function and click OK, Minitab prompts you to choose predictors for each placeholder.
- Choose predictors
- Minitab automatically lists the placeholder that it detects within the expectation function. Enter the column that contain the actual predictor variable for each placeholder.

- Manage My Functions
- You can rename, assign a category, or delete custom functions in the catalog. Each time you perform nonlinear regression with a new custom function, Minitab adds the function to the catalog and assigns it a default name and category. Use the features in this dialog box to improve how the catalog displays and filters the custom functions.

Use the calculator to enter an expectation function that contains arithmetic operations, comparison operations, logical operations, functions, and column operations. Expressions may include columns, stored constants, numbers, operations, and functions, but not matrices. For more information, go to How to specify the expectation function in nonlinear regression.

- Expectation function
- Enter the mathematical function that you want Minitab to use for the nonlinear regression. Select variables, buttons, and functions to create your expression. For more information, go to Create a formula with the Calculator.
- Functions
- Select a category of calculator functions to filter the list of functions. For more information, go to Calculator functions.