SWIN BUR · NE . Swinburne Online STA10003 Top 50 Terms Population A population is the entire collection of sampling units that data can be sampled from. Sample A sample is a smaller subset of a population. The word sample can also be used as a verb (e.g. to 'sample' or collect data). Bias Bias represents a systematic favouritism towards a particular sample group or design element in a study. Proportion A small part or share of a number. A proportion is similar to a percentage, however is represented as a decimal (e.g. 0.50 is the same as 50%). Term Percentage A way in which we present data, as a rate or factor of 100. Similar to a proportion (e.g. a proportion of 0.25 is the same as 25%). Week 2 Metric Variable A variable which is measured on an interval or ratio scale. An example of a metric variable is height measured in centimetres. Categorical Variable A variable which is measured in defined groups or categories. An example of a categorical variable is sex (male or female). Frequency Table A table, appropriate for categorical variables, which includes the number of cases in each category. Boxplot A plot which summarizes data of a metric variable, where a rectangle is drawn to represent the 25th and 75th percentiles. A middle value is drawn to represent the median and horizontal lines drawn on either side of the rectangle, which represent the lower and upper quartiles. Bar graph A graphical version of a frequency table. In a bar graph, data of a categorical variable is displayed using horizontal or vertical bars. As the bars represent different categories, there should be spaces between the bars in a bar graph. Histogram A histogram shows the distribution of a metric variable, presenting the frequency of each individual scores. Similar to a bar graph, however as the x axis represents a continuous scale, rather than individual groups, there are no gaps between the bars in a histogram. Mean The mean, more commonly known as the average, is equal to the sum of all scores divided by the number of scores. Median The median is the middle value of a variable, when all values are listed in ascending order. Mode Standard Deviation The standard deviation is by how much the scores in a variable deviate from the mean, on average. It gives an indication of how much variability or spread there is in a variable. Definition Week 1 Week 3 The mode is the most commonly occurring value in a given variable. Page 1 Top 50 terms Created By Swinburne Online August 2016
Z scores A standardised unit of measurement, where a variable is expressed in units of standard deviations away from the mean. The mean Z score is equal to 0. Normal Distribution A commonly occurring distribution in nature, where the mean, median and mode are all equal, with variation around this central measure forming a symmetrical bell curve. Sampling Distribution of the Mean/Proportion A theoretical distribution