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en:create:random_questionnaire [05.02.2015 11:23] – [Weighted Random Selection] alexander.ritter | en:create:random_questionnaire [29.07.2019 19:22] – admin | ||
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====== Random Selection for Questionnaires ====== | ====== Random Selection for Questionnaires ====== | ||
- | Multiple questionnaires can be created in one survey project (**Compose | + | In a survey project |
+ | **Note:** For experiments it is usually much easier (!) to create only one questionnaire and vary the stimulus with a small PHP code ([[: | ||
- | **Note:** Random selection of questionnaires has some restrictions (see notes below) and this option is __only__ sensible __in a few__ exceptional cases. As a rule, it makes much more sense to use normal [[randomization|randomization]]. | ||
- | ===== Notes ===== | + | ==== How-to |
- | Selection or random selection takes place every time the project folder is selected without a specific | + | First you create an additional |
- | In an unrestricted random selection, the different conditions will usually usually drawn an unequal (!) number of times. If 100 people are spread across 5 groups, the groups could be distributed | + | Define this questionnaire |
- | The same goes for a weighted random selection: as a rule, approximation to the desired distribution only occurs in the region of larger numbers (n > 1000). Statistical outliers are therefore not possible either. | + | {{:de: |
- | The questionnaire | + | To ensure an equal distribution of the participants on the questionnaires, |
+ | {{: | ||
- | ===== Set Questionnaire | + | Enter the IDs of the questionnaires (see above) you want to choose between |
- | One of the questionnaires will be used as default | + | Leave the default |
+ | {{: | ||
- | If only one questionnaires exists in the survey project then this questionnaire | + | Open the questionnaire |
+ | - Drag the random generator (RF01) to the first (and only) page of the questionnaire, | ||
+ | - place the following [[: | ||
- | ===== Random Selection from Selected Questionnaires ===== | + | <code php> |
- | + | $qnr = value(' | |
- | One or more questionnaires can be selected with this option. If the URL is called up without a questionnaire being specified | + | goToQuestionnaire($qnr); |
- | + | </ | |
- | **Note:** As a rule, an unrestricted random selection results in questionnaires being called up different numbers of times. Therefore, please take the information above into consideration. | + | |
- | + | ||
- | + | ||
- | ===== Weighted Random Selection ===== | + | |
- | + | ||
- | Weighted random selection represents an extension of a random selection. The principle is the same as a random selection: one of the questionnaires from those with specified weighting | + | |
- | + | ||
- | Questionnaires with a higher weighting are therefore chosen with a correspondingly higher probability. The specific numbers that are input is not important, what matters is the relation: a questionnaire with a weighting of 2 will be (for example) selected twice as often as one with a weighting of 1. A questionnaire with a weighting off 66 will be selected twice as often as a questionnaire with a weighting of 33. | + | |
+ | The function '' | ||
+ | {{: |