Chapter 5 Glossary Flashcards
What is an abscissa?
The x axis on a graph.
What is the alpha level?
Type 1 error level (probability of incorrectly rejecting the null hypothesis).
What is the analysis of variance?
Statistical procedure that analyses mean differences between two or more groups by comparing between-groups and within-group variance.
What is average deviation?
The average distance from the mean.
What is beta?
The probability of making a type two error.
What is bimodal?
A distribution of scores that has two modes.
What is central tendency?
Average or typical score in a distribution.
What is a coefficient alpha?
An index of internal consistency reliability.
What is continuous variable?
Variable that can theoretically take on an infinite number of values.
What is a correlation coefficient?
Index of the degree of linear relationship between variables.
What is correlation?
Degree of linear relationship between two or more variables.
What is covary?
When the values of two or more measures change together.
What is cross-tabulation?
Procedure that illustrates the relationship between two or more nominal variables. A cross tabulation table shows the frequency of participants who show each particular combination of characteristics.
What is a degree of freedom?
A statistical concept in which one degree of freedom is lost each time that a population parameter is estimated.
What are descriptive statistics?
Statistics that summarise and/or describe a sample of scores.
What are effect size?
Index of the size of the difference between groups, expressed in standard deviation units.
What are frequencies?
The number of objects or participants that fall into a specified category.
What is frequency distribution?
Organisational device used to simplify large data sets.
What is a frequency polygon?
Graph that illustrates a frequency distribution by placing a dot above each possible score at a height that indicates the score’s frequency and then connect the dots.
What are graphs?
A means of presenting data visually.
What are grouped frequency distribution?
Lists the frequency of scores in equal-size intervals.
What is a histogram?
A bar graph in which the frequency of scores is represented by the height of the bar.
What are individual differences?
Natural difference among people.
What are inferiental statistics?
Statistical procedures that allow us to decide whether the sample data suggest that population difference exist.
What is linear relationship?
Relationship between the variables that, when plotted in a standard coordinate system, cluster around a straight line.
What is a mean?
Arithmetic average of scores that should be computed only for score data.
What are measures of central tendency?
Descriptive statistics that indicate the typical score.
What is median?
Middle score in a distribution.
What is mode?
Most frequent score in a distribution.
What is a negative correlation?
Relationship between two variable in which an increase in one variable predicts a decrease in the other.
What is negatively skewed?
When scores are concentrated near the top of the distribution.
What is a non linear relationship?
Any relationship between variables that is characterised by a scatter plot in which the points cluster around a curve instead of a straight line.
What is normal distribution?
Distribution of scores that is characterised by a bell shaped curve. Psychological variables tend to show distributions that are close to normal.
What is null hypothesis?
States that the groups are drawn from populations with identical population perimeters.
What is an ordinate?
The y axis on a graph.
What is pearson product-moment correlation?
Index of the degree of linear relationship between two variables in which each variable represents score data.
What is a percentile rank?
Score that reflects the percentage of participants who score lower.
What is perfect correlation?
Correlation of a 1 or a -1
What is phi?
A measure of relationship between two nominal variables.
What is population?
A defined set of objects or events (people, occurences, animals etc).
What is a positive-correlation?
Relationship between two variables, in which one variable increases as the other variable
What is positively skewed?
Distribution in which scores are concentrated near the bottom of the scale.
What is power?
Power of a statistical test is the ability of an inferential statistical procedure to detect differences between groups when such differences actually exist.
What is power analysis?
Procedures that determine the power of a statistical tst to detect group differences if those differences exist.
What is probability?
The ratio of speific events to the total number of possible events.
What is p value?
The probability of obtaining the statistic or a larger statistic by chance if the null hypothesis is true.
What is range?
Distance between he lowest score and the highest score.
What is regression?
A mathematical procedure that produces an equation for predicting a variable (the criterion) from one or more other variables.
What is relationship?
Any connection between two or more variables.
What is a sample?
Any subset drawn from a population.
What is sampling error?
Chance variation among samples drawn from the same population.
What is a scatter plot?
Graphing technique that
What is skewed distribution?
Any distribution in which scores bunch up at the end of the scale.
What is spearman rank-order correlation?
Indexes the degee of the relaiationship between two variables, each of which is measured on at least an ordinal scale.
What is standard deviation?
An index of variability that is the square root of the variance.
What is standard score?
Score that gives a person relative standing. It is computed by subtracting the mean from the score and dividing by the standard deviation.
What is statistical power?
Power of a statistical test
What is statistical signifigance?
A finding is statistically significant if it us unlikely that it occurred by chance alone.
What is sum of squares?
Sum of the squared fiferences from the mean.
What is symmetric distribution?
Distribution in which the right half of the distribution is a mirror image of the left half.
What is trimodal?
A distrubution that has three modes.
What is a t-test?
Statistical procedure that tests for mean differences between two groups.
What is a type 1 error?
Probabability of rejecting the null hypothesis when it is true.
What is a type 2 error?
Probability of not rejecting the null hypothesis when it is false.
What is unvariate design?
Single-variable designs: Designs that include just one independent variable.
What is variability?
Differences among participants on any given variable.
What is variance?
Summary statistic that indicates the degree of variability among participants.
What is x-axis?
The horizontal axis in a graph.
What is a y axis?
The vertical axis in a graph.
What is a z score?
A standard score.
