# Lab10

**Lab 10**

**Pol242 Lab Manual: Lab 10**

**Applying Weights**

**Purpose**

- To Practice applying weights to survey data
- To Use the Weight command to enter published tables into SPSS

**Main Points**

- The samples from which survey data are collected often do not match the population they are intended to represent.
- Researchers therefore often weight their data for analysis.
- Data sets often contain one of more data weights for use in analysis.
- Consulting the codebook will provide information on the appropriate .weights to use
- The SPSS command is: Weight by
- In the CES the appropriate variable is WGTSAMP
- In the ANES the appropriate variable is weight_full

**Example 1**

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**Data Set**

CES2011

**Syntax**

*Weighting the Data*. Weight by WGTSAMP. *Using Syntax from Lab 1*. *Preparing a Y indicator-Cdn Attitudes re Inequality* missing values pes11_41 (8,9). recode PES11_41 (1=1) (2=.75) (3=.5) (4= .25) (5=0) into undogap. value labels undogap 0 'muchless' .25 'someless' .5 'asnow' .75 'somemore' 1 'muchmore'. *frequency analysis for Y*. fre var undogap. *Preparing the X indicator- party identification*. recode cps11_71 (2=1) (1=2) (4=3) (3=4) (5=5) (6 =6) into PID. value labels PID 1 'Cons' 2 'Lib' 3 'BQ' 4 'NDP' 5 'Green' 6 'None'. *frequency analysis for Y1*. fre var PID.

**Syntax Legend**

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The weight command is used prior to the syntax used in Lab 1.

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**Output**

undogap |
|||||

Frequency | Percent | Valid Percent | Cumulative Percent | ||

Valid | muchless | 49 | 1.4 | 2.0 | 2.0 |

someless | 60 | 1.7 | 2.4 | 4.3 | |

asnow | 511 | 14.8 | 20.4 | 24.8 | |

somemore | 969 | 28.0 | 38.7 | 63.5 | |

muchmore | 914 | 26.4 | 36.5 | 100.0 | |

Total | 2503 | 72.3 | 100.0 | ||

Missing | System | 959 | 27.7 | ||

Total | 3462 | 100.0 |

PID |
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Frequency | Percent | Valid Percent | Cumulative Percent | ||

Valid | Cons | 897 | 25.9 | 28.3 | 28.3 |

Lib | 806 | 23.3 | 25.4 | 53.7 | |

BQ | 290 | 8.4 | 9.1 | 62.9 | |

NDP | 371 | 10.7 | 11.7 | 74.6 | |

Green | 84 | 2.4 | 2.6 | 77.2 | |

None | 722 | 20.9 | 22.8 | 100.0 | |

Total | 3170 | 91.6 | 100.0 | ||

Missing | System | 292 | 8.4 | ||

Total | 3462 | 100.0 |

**Interpretation of Output**

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These results differ somewhat from those reported in Lab 1.

These figures more closely represent the population values than those reported in Lab 1.

**Example 2**

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Entering Published crosstabulations into SPSS

- Another use of the Weight command is to enter crosstabulated data.
- This is handy when you wish to calculate measures of association or statistical significance for a published crosstabulation.
- On the data list command the variable names are listed DV first and IV second. A third variable called count represents the number of cases a cell.
- The cell entries are entered using he coordinates for the table. The first number defines the row, the second defines the column. The third number is the number of cases in the cell defined by the row and column numbers.
- Variable labels and value labels are entered as usual.
- The weight command tells SPSS how many cases to put in the cells.
- The crosstabulation follows the usual pattern.

**Entering Crosstabulated Data**

**(Using data from a paper under review at CJPS)**

*Aboriginal Attitudes Paper for CJPS*. data list free / influence group count. begin data. 1 1 19 1 2 330 2 1 25 2 2 525 3 1 20 3 2 420 4 1 32 4 2 225 end data. variable labels influence 'undue influence' group 'group'. value labels influence 1 'Str Agree' 2 'Some Agree' 3 'Some Disagree' 4 'Str Disagree'. value labels group 1 'Aborig' 2 'not'. weight by count. crosstabs tables = influence by group /cells = column count /statistics = all.