Identify the conditions of the independent variable , the dependent variable , their scales of measurement , which measure of central tendency and variability to compute and which scores you would use in the computation . We test whether participants laugh longer ( in seconds ) to jokes told on a sunny or rainy day . We test whether babies whose mother's were or were not recently divorced , measuring whether the babies lost weight , gained weight , or remained the same . We compared a group of adult children of alcoholics to a group whose parents were not alcoholics. In each , we measure participants income . We count the number of creative ideas produced by participants who are paid either 5 , 10 , or 50 cents per idea . We measure the number of words in the vocabulary of 2 year-olds as a function of whether they have 0,1,2 or 3 older siblings .
An independent variable is the potential stimulus or cause, usually directly manipulated by the experimenter, so it could also be called a manipulative variable.
A dependent variable is the response or measure of results.
1. Testing whether participants laugh longer (in seconds) to jokes told on a sunny or rainy day:
- Independent variable: Weather conditions (sunny or rainy day)
- Dependent variable: Duration of participants' laughter (in seconds)
- Scale of measurement:
- Independent variable: Nominal scale (categories: sunny, rainy)
- Dependent variable: Ratio scale (continuous measurement in seconds)
- Measure of central tendency: Mean (to determine the average duration of laughter across the two weather conditions)
- Measure of variability: Standard deviation (to assess the variability or spread of laughter durations)
- Scores used in computation: The duration of laughter for each participant for each weather condition.
2. Testing whether babies whose mothers were or were not recently divorced lost weight, gained weight, or remained the same:
- Independent variable: Mothers' divorce status (recently divorced or not)
- Dependent variable: Change in babies' weight (lost weight, gained weight, remained the same)
- Scale of measurement:
- Independent variable: Nominal scale (categories: recently divorced, not recently divorced)
- Dependent variable: Nominal scale (categories: lost weight, gained weight, remained the same)
- Measure of central tendency: Mode (to determine the most frequently observed change in weight)
- Measure of variability: Percentages or proportions (to assess the distribution of weight changes)
- Scores used in computation: The change in weight category for each baby based on their mothers' divorce status.
3. Comparing a group of adult children of alcoholics to a group whose parents were not alcoholics, measuring participants' income:
- Independent variable: Parental alcoholism (children of alcoholics or children of non-alcoholics)
- Dependent variable: Participants' income
- Scale of measurement:
- Independent variable: Nominal scale (categories: children of alcoholics, children of non-alcoholics)
- Dependent variable: Ratio scale (continuous measurement in currency, e.g., dollars)
- Measure of central tendency: Mean (to determine the average income difference between the two groups)
- Measure of variability: Standard deviation (to assess the variability or spread of incomes within each group)
- Scores used in computation: The income of each participant for each group (children of alcoholics and children of non-alcoholics).
4. Counting the number of creative ideas produced by participants who are paid either 5, 10, or 50 cents per idea:
- Independent variable: Payment amount (5 cents, 10 cents, 50 cents per idea)
- Dependent variable: Number of creative ideas produced
- Scale of measurement:
- Independent variable: Ratio scale (continuous, numeric values representing payment amount)
- Dependent variable: Ratio scale (whole numbers representing the count of creative ideas)
- Measure of central tendency: Mean (to determine the average number of creative ideas for each payment amount)
- Measure of variability: Standard deviation (to assess the variability or spread of the number of ideas within each payment group)
- Scores used in computation: The count of creative ideas for each participant for each payment amount.
5. Measuring the number of words in the vocabulary of 2-year-olds as a function of the number of older siblings (0, 1, 2, or 3):
- Independent variable: Number of older siblings (0, 1, 2, or 3)
- Dependent variable: Number of words in the vocabulary of 2-year-olds
- Scale of measurement:
- Independent variable: Ordinal scale (ordered categories: 0, 1, 2, 3)
- Dependent variable: Ratio scale (whole numbers representing the count of words)
- Measure of central tendency: Mean (to determine the average number of words for each number of older siblings)
- Measure of variability: Standard deviation (to assess the variability or spread of the number of words within each sibling group)
- Scores used in computation: The count of words in the vocabulary for each 2-year-old participant based on their number of older siblings.