Chapter 7 summering and interpreting data Flashcards
Sampling error
The difference between the observation in a population and in the sample that represents that population in a study
Descriptive statistics
Measure that help us summarize data sets
Inferential statistics
A set of statistical procedures used by researchers to test hypotheses about population
Distribution
A set of scores
Central tendency
Representation of a typical score in a distribution
Variability
The spread of scores in a distribution
Mean
The calculated average of the scores in a distribution
Median
The middle score in a distribution, such that half of the scores are above and half are below the value
Mode
The most common score in a distribution
Outliners
Extreme high or low scores in the distribution
Reaction time
Measurement of the length of time to complete a task
Range
The difference between the highest and the lowest score in a distribution
Standard deviation
A measure representing the average difference between the scores and the mean of a distribution
Variance
The standard deviation of a distribution squared
Degrees of freedom
Number of scores that can vary in the calculation of a sadistic
Frequency distribution
A graph of a distribution showing the frequency of each response in the distribution
Bar Graph
A graph of the means for different conditions in a study where the bar height represents the size of the mean
Line graph
A graph of the means for different conditions in a study where each mean is graphed as a point and the points are connected in a line to show differences between mean scores
Scatterplot
A graph showing the relationship between two dependent variables for a group of individuals
Predictor variable
The dependent variable in a correlational Study that is used to predict the score of another variable
Outcome variable
The dependent variable in a correlational study that is being predicted by the predictor variable
Scientific/alternative hypothesis
Hypothesis that in effect or relationship exist ( or exists in a specific direction) in the population
Null hypothesis
The hypothesis that an effect or relationship does not exist ( or exists in the opposite direction of the alternative hypothesis) in a population
Two-tailed hypothesis
Both directions of an effect or relationship are considered in the alternative hypothesis of the test
One-tailed hypothesis
Only one direction of an effect or relationship is predicted in the alternative hypothesis of the test
Distribution of sample means
The distribution of all possible sample means for all possible samples from a population
Confidence intervals
A range of values that the population mean likely falls into with a specific level of certainty
Alpha level
The probability level used by researchers to indicate the cut off probability level (highest value) that allows them to reject the null hypothesis.
P value
Probability value associated with an inferential test that indicates the likelihood of obtaining the data in a study when the null hypothesis is true
Significant test
The P value is less than or equal to Alpha In an inferential test, and the null hypothesis can be rejected
Critical region
The most extreme portion of a distribution Of statistical values for the null hypothesis determined by the alpha level (typically 5%)
Type l error
Error made in a significance test when the researcher rejects the null hypothesis when it is actually true
Type II error
Error made in a significance test when the researcher fails to reject the null hypothesis when it is actually false
Power
Ability of a significance test to detect an effect or relationship when one exists ( equal to 1- the probability of a type II error)
