Table Of Contents

- Manual
- Getting Started
- Starting the Program
- Retrieving Data
- Manipulating Data
- The Variable List
- The Variable List Menu
- Filter Observations/Selecting
- Add New Variables
- Delete Variables
- Edit Metadata
- Set Replicate Weights
- New Variable Reserve
- Edit Value Labels
- Dummy Code Categorical Variable
- Collapse Categories of Categorical Variable
- Set Missing Values
- The Expression Evaluator

- Saving and Re-running Actions

- Sampling
- Procedures
- Measurement Models
- MML Models for Test Data
- Other Available Procedures

- Graphics
- Tools
- Estimation Methods
- Optimization Techniques
- Variance Estimation

- Post-hoc Procedures
- More user input instructions
- The User Interface
- Input Instructions
- Options
- Output Precision

- Glossary of Terms and Symbols

- Getting Started

The Expression Evaluator

Currently, *AM* uses a very primitive expression evaluator. It is slated for replacement very soon.

Comparisons return a one if true and a zero if false. The comparison operators are:

Symbol |
Meaning |

< |
Is less than |

> |
Is greater than |

<= |
Is less than or equal to |

>= |
Is greater than or equal to |

= |
Is equal to |

<> |
Is not equal to |

The arithmatic operators are:

Symbol |
Meaning |

+; |
Addition |

-; |
Subtraction |

* |
Multiplication |

/ |
Division |

% |
Modulus--the remainder after division |

^ |
Exponent, the preceding number to the power of the following number |

Log(x) |
Natural logarithm of x (base |

Log10(x) |
Base 10 logarithm of x |

rand(x) |
Uniform random number, takes x as the seed |

Parentheses should be used to group operations where the order of precedence is not clear. Suppose that you have variables A and B and you want to multiply them and square the result. You would write:

(A*B)^2

Of course, this is equal to:

A^2*B^2

since the standard order of precedence exponentiates first. For a square root of this we could write:

(A^2*B^2)^(1/2)