Term | Definition |
Q1 First Quartile Lower Quartile | The median of the lower(first)half of a data set. |
5-point summary | The lower extreme value
The first quartile
The Median
The third quartile
The upper extreme value |
biased sample | A sample in which members are not randomly selected |
box plot (box-and-whisker-plot) | A graphical display of the five point summary |
inference | a conclusion about a population made by projecting the results or a representative sample onto the whole population |
interquartile range | The difference between Q3 and Q1 |
leaf | the least digit in each item of a data set when displayed in a stem and leaf plot |
Q2 Median Second Quartile | The middle value of a data set |
MAD | The average distance of the data values from the Mean |
measure of variation | How the data varies between quartiles and other important data points. A measure of the spread of data from a measure of center |
population | All the members or objects about which you want information |
random sample | a set of data randomly selected from a population so that every member of the population has an equal chance of being selected |
range | the greatest value minus the least value in a data set |
sample | a set of data taken from a population |
sample size | The number of members in a sample |
Q3 Upper Quartile Third Quartile | The median of the upper(second)half of a data set |
simple random sampling | a sampling method in which every member of the population has an equal chance of being selected |
stem | all digits except for the one of the least place value in an item of data displayed in a stem and leaf plot |
stem-and-leaf plot | a two-column graphical display in which the least digit of each item is displayed on the right and the other digits in the left |
stratified random sampling | a sampling method in which the population is divided into non overlapping groups from which members are randomly selected |
systematic random sampling | a sampling method in which the first member is randomly selected and the subsequent members are selected at regular intervals |
unbiased sample | same as a random same |