Applied Probability and Statistics (WGU) Question And Answers

Applied Probability and Statistics (WGU) Question And Answers relative frequency a way to approximate a percentage by dividing the number of times an event occurred by the number of trials frequency distribution a record of the number of times data occurs within a certain category outliers an observation point (number) that is distant from the other observations of a data set center a measure of central tendency that is used to describe an entire set of data with one value that represents the middle or center of the distribution (mean, median, mode) interval a set of numbers between two specified values check sheet a table that allows data to be collected by marking how often an event has occurred in a certain interval symmetric distributions the left half of a data set being roughly identical to the right half bell curve normal distribution, results from graphing frequency versus distribution for a trait that varies continuously in a population skewed-right type of data distribution where frequency starts small, increases, then gradually decreases again skewed-left distribution where data starts small and consistently increases before dropping off again u-shaped distribution where data in the middle is lower than the data on the left or right uniform distribution where all data is virtually the same bimodal data set with only two peaks multimodal data set with multiple peaks statistics the collection and classification of data that are in the form of numbers reliable data data that is consistent and repeatable valid data data resulting from a test that accurately measures what it was intended to measure five number summary lists the minimum, first quartile, median, third quartile, and maximum in a data set quartiles divides data into four equally sized groups interquartile range difference between the third quartile and the first quartile normal symmetric (measures of center and spread) mean; standard deviation skewed (measures of center and spread) median; range or interquartile range explanatory variable (independent variable) the cause of some result response variable (dependent variable) the affected or changed variable C→C both variables are categorical; displayed in a two way frequency table (contingency table) C→Q categorical and quantitative; displayed in with side by side box plots Q→Q quantitative to quantitative; displayed in a scatterplot correlation coefficient a number that falls somewhere from -1 to 1 the closer to 0, the weaker the linear relationship cluster a grouping of a number of similar things away from the majority of points in a data set population all subjects in a study which have the characteristics being evaluated distribution an arrangement of values that demonstrates their frequency or occurrence pie chart categorical data, % bar chart categorical data; displays counts or frequencies for a category dot plot quantitative data, data is represented by a single point stem plots quantitative data, shows distribution while representing specific data points box plots quantitative data, can be used to compare data sets, each part is 25% of data histograms quantitative data, display frequencies or counts