click below

click below

Normal Size Small Size show me how

# Willard Ch 14

### Statistics

Term | Definition |
---|---|

correlation coefficient | A number, ranging from -1.00 to +1.00, that measures the direction and strength of the relationship between two variables |

positive correlation | Relationship in which two variables proceed in the same direction: high X scores are associated with high Y scores, and vice-versa. |

negative correlation | Relationship in which two variables proceed in opposite directions: high X scores are associated with low Y scores, and vice-versa. |

perfect correlation | In a perfect correlation, many of the dots will be piled on top of each other and, when connected, will form a straight diagonal line. |

coefficient of determination | Proportion of variance that two variables share in common; proportion of the variance on one variable that is explained by the variance of the other. |

coefficient of non-determination | Proportion of variability that is not shared, common variance; proportion of the variance on one variable that is not explained by the variance of the other. |

linear relationship | described by a straight line in which there is a tendency for Y scores to move in only one direction in relation to the X scores. |

regression analysis | Statistical procedure used to predict the value of a score on one variable by knowing the value of the score on another variable. |

slope | tells us how much and in what direction the regression line slants. |

y-intercept | point where the regression line cuts across, or intercepts, the Y-axis. |

regression equation | An equation for the line of best fit, which is used to predict Y values from given X values. |

restricting the range | When a sample is used that limits the scores on one or both variables more so than would be found in the population. |

outliers | scores on either the X or Y variable that are extreme. Can have a dramatic effect on the magnitude of the correlation. |

Scatterplot | diagram of the relationship between two variables. Positive correlations ascend to the right. Negative correlations decend to the right. More scatter= weaker correlation. |

Pearson correlation | Used for examining linear relationships between variables measured on interval or ratio scales. |