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37 Cards in this Set
- Front
- Back
What are the 2 branches of statistical methods and how are they used? |
Descriptive statistics: used to summarize and describe a group of numbers from a research study. Inferential statistics: used to draw conclusions and to make inferences that are based on the numbers from a research study but that go beyond the numbers. |
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Variable |
Characteristic that can have different values. Ex) height, weight, social class, score on a test. |
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Value |
Possible number or category that a score can have. |
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Score |
A particular person's value on a variable. |
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What is the other name for a numeric variable? |
Quantitative variable |
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Numeric variable |
Variable whose values are numbers |
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Equal-Interval Variable |
Variable in which the number stands for approximately equal amounts of what is being measured. |
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Rank-ordered variables |
Numeric variable in which the values are ranks. |
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Ratio scale |
An equal-interval variable is measured on a ratio scale if it has an absolute zero point. |
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Nominal/categorical variable |
Variable with values that are categories rather than numbers |
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Discrete variable |
A variable that has specific values and cannot have values between the specific values |
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Continuous variable |
There's an infinite number of values between every two values |
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Unimodal |
If a distribution has only one high point. |
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Bimodal |
If a distribution has two equal high points. |
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Rectangular distribution |
All points are equal |
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Positive skew |
Tail goes toward the positive numbers |
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Negative skew |
Tail goes toward the negative numbers. |
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Central tendency |
Typical or most representative value of a group of scores. |
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What are the three measures of central tendency? |
Mean, median, mode |
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What is the formula for variance? |
SD^2= E (X-M)^2/N |
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What is the formula to turn a raw score to a Z-score? |
Z= (X-M)/SD |
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What is the formula to turn a Z-score into a raw score? |
X=(Z)(SD)+M |
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Sample |
Scores from a particular group of people studied. A smaller representative group of the population. |
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Population |
The entire group of people to which a researcher intends the results of a study to apply. This is a larger group to which inferences are made on the basis of the sample studied. |
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Population parameters |
The mean, variance, and SD of a population |
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Sample statistics |
The mean, variance, and SD you figure for the scores in a sample |
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Probability |
Expected relative frequency of a particular outcome |
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Outcome |
The results of an experiment |
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How do you find the probability? |
Possible successful outcomes/all possible outcomes |
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What is the range if probability |
From 0 to 1 (or 1% to 100%) |
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Can probability be negative? |
No |
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Hypothesis |
A prediction intended to be tested in a research study. |
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Theory |
A set of principles that attempt to explain an important psychological process. |
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What does a theory usually lead to? |
various specific hypotheses that can be tested in research studies. |
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1-tailed test |
The direction of the result is predicted (one directional) |
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2-tailed test |
Direction of the result is not predicted (could go either pos or neg) |
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When should you reject the null hypothesis? |
When the sample is outside the cutoff values (critical value) |