What is an alternative hypothesis? | a statement about the value or values of a population parameter. A hypothesis proposed as an alternative to the null hypothesis |

What is a bar chart? | A graphic display of the data in a frequency or percentage distribution. |

What is a bimodal distribution? | frequency distribution with two different values that are heavily populated with cases |

Define central tendency. | the most frequent, middle, or central value in a frequency distribution |

What is a confidence interval? | the range of values into which a population parameter is likely to fall for a given level of confidence |

What is a confidence level? | the degree of belief or probability that an estimated range of values includes or covers the population parameter |

What is a cumulative proportion/percentage? | the total proportion of observations at or below a value in a frequency distribution |

What is a data matrix? | an array of rows and columns that stores the values of a set of variables for all the cases in a data set |

What is a descriptive statistic? | the mathematical summary of measurements for one variable |

What is deviation? | The deviation of an observation from the sample mean is the difference between them. |

What is dispersion? | the distribution of data values around the most frequent, middle, or central value |

What is the empirical rule? | If the histogram of the data is approximately bell shaped, then (1) about 68% of observations fall within one standard deviation of the mean, (2) about 95% of observations fall within two standard deviations of the mean, and (3) nearly all of observations fall within three standard deviations of the mean. |

What is a frequency distribution (f)? | the number of observations per value or category of a variable |

What is a histogram? | a type of bar graph in which the height and area of the bars are proportional to the frequencies in each category of a nominal variable or intervals of a continuous variable |

What is an index? | A multi-item measure in which individual scores on a set of items are combined to form a summary measure. |

What is an index of diversity? | a measure of variation for categorical data that can be interpreted as the probability that two individuals selected at random would be in different categories |

What is an index of qualitative variation? | a measure of variation for categorical data that is the index of diversity adjusted by a correction factor based on the number of categories of the variable |

What is an interquartile range? | the middle 50 percent of observations |

What is an interval-level variable? | A measure for which a one-unit difference in scores is the same throughout the range of the measure. |

What is a Likert Scale? | A multi-item measure in which the items are selected based on their ability to discriminate between those scoring high and those scoring low on the measure. |

What is a mean? | the sum of the values of a variable divided by the number of values |

What is mean absolute deviation? | a measure of dispersion of data points for interval- and ratio-level data |

What is a median? | the category or value above and below which one-half of the observations lie |

What is a mode? | the category with the greatest frequency of observations |

What is negative skew? | a distribution of values in which fewer observations lie to the left of the middle value and those observations are fairly distant from the mean |

What is a nominal-level variable? | A measure for which different scores represent different, but not ordered, categories. |

What is an ordinal-level variable? | A measure for which the scores represent ordered categories that are not necessarily equidistant from each other. |

What is an outlier? | An observation is an outlier if it fails more than 1.5(IQR) above the upper quartile or more than 1.5(IQR) below the lower quartile (IQR = interquartile range). |

What is a percentile rank? | reports the percentage of cases in a distribution that lie below it (ex: 97th percentile on the SAT) |

What is a pie diagram? | a circular graphic display of a frequency distribution |

What is positive skew? | a distribution of values in which fewer observations lie to the right of the middle value and those observations are fairly distant from the mean |

What is raw frequency? | The total number of observations with a particular value (such as the number of respondents giving a certain response). |

What is relative frequency? | percentage or proportion of total number of observations in a frequency distribution that have a particular value |

What is relative frequency? | The relative frequency for a category is the proportion or percentage of the observations that fall in that category. |

What is a resistant measure of central tendency? | a measure of dispersion of central tendency that is not sensitive to one or a few extreme values in a distribution |

What is the standard normal distribution? | normal distribution with a mean of 0 and a standard deviation and variance of 1 |

What is statistical significance? | the probability of making a type I error |

What is a total frequency? | The sum of raw frequencies (usually presented in a table). |

What is a trimmed mean? | the mean of a set of numbers from which some percentage of the largest and smallest values has been dropped |

What is a variable? | A characteristic that can vary in value among subjects in a sample or population. |

What is intercoder reliability? | demonstration that multiple analysts, following the same content analysis procedure, agree and obtain the same measurements |

What is an additive index? | Summation of ordinal variables, each of which is coded identically, and all of which are measures of the same concept. Also called a summative scale or ordinal scale. |

What is automated content analysis? | Content analysis, which entails transforming non-numeric text into numeric data, done through automated programs or algorithms. |

What is centrality (in a network)? | In regards to social networks, is the importance of nodes in the network based on their connections – nodes with more connections are viewed as being more central. |

What is a density plot? | Alternative to histograms, display a “running average” of observations across the range of observed values. Also called kernel density plots. |

What is mean centering? | Process that involves subtracting the mean value of the variable from each observed value. |

What is network analysis? | Process of transforming evidence of social connections among people into quantitative measures and maps of social structures that explain political phenomena or other social phenomena. |

Define range (of a variable). | Measure of variability of data, determined by subtracting the minimum value from the maximum value. |

What is skewness? | Measure of symmetry of data, relates to variability – the more skewed a data set is, the less symmetrical it is. |

What is standard deviation? | Measure of variability, summarizes the extent to which the cases in an interval-level distribution fall on or close to the mean of the distribution. It is the square root of the variance. |

What is standardizing? | Process of relating scores to the mean using the standard deviation – dividing the difference from the mean by the standard deviation of scores yields standardized scores that are independent of characteristics of the assessment. |

What is variance? | A summary of the dispersion of an interval-level variable. The sum of squared deviations divided by n-1. The square root of which is the standard deviation. |