Question | Answer |
Range | the difference between the highest and lowest values. It can be stated in two ways from low to high (2-12) or the difference (10) |
Line Plot | a display of data that shows how many times each data value occurs. Each time a data value occurs, a mark is made above that value on a number line. (Example 1, page 7) |
Stem-and-Leaf diagram | a diagram that uses digits of data numbers to show the shape and distribution of a data set. Each data number is separated into a stem and leaf. (Example 2, page 7) |
Double Stem-and-Leaf Diagram | a diagram that compares two sets of data in one diagram. (Example 3, page 8) |
Measure of Central Tendency | a single value that summarizes a set of numerical data. Types are mean, median, and mode. |
Mean | the sum of a set of data divided by the number of data, also called the average. (Example 1, page 12) |
Median | the middle value of a data set. Data must be arranged in order to be identified. For even number of data points, take the mean of the two mid data points. (Example 3, page 13) |
Outliers | extreme values separated from most of the data set which will skew data averages. (Example 2, page 12) |
Mode | the most common data value. If no value occurs more than once, there is none. |
Box-and-Whisker Plot | a visual way of showing median values for a set of data. The whiskers represent the range. (Example 1, page 18) |
Quartiles | three numbers that divide a data set into four equal parts. The median is used for middle quartile. The median of the first half divides two upper quartiles. The median of the second half divides the two lower quartiles. (Example 2, page 19) |
Lower Quartile | the median of the lower half of the data set. |
Upper Quartile | the median of the upper half of the data set. |
Bar Graph | a diagram that uses bars to represent the value of a data set. It is used to compare data from several situations. (Example 1, page 23) |
Double Bar Graph | a diagram that shows two bar graphs together and compares two related data sets. (Example 2, page 24) |
Line Graph | a line drawn through a pair of associated numbers on a grid, usually shows changes over time. (Example 3, page 24) |
Double Line Graph | a diagram that shows two line graphs together to compare two related data sets. (Example 4, page 25) |
Population | the collection of all things to be studied. |
Sample | a part of a population. |
Random Sample | an unbiased sample that is representative of a population (Example 2, page 33.) |
Tally | a quick record of a count taken during a survey |
Frequency | the number of times something occurs in a survey |
Frequency Table | shows classes of things, a tally, and how often they occur (Example 1, page 38) |
Histogram | a type of bar graph where the categories are numeric (Example 2, page 39) |
Scatterplot | a graph showing a set of points based on two data sets |
Trend | a pattern formed by points on a scatterplot |
Trend Line | a representation that approximately “fits” points forming a pattern that can be positive or negative; can also form no pattern (Example 1, page 43) |
What is the best method of showing counting and data values? | Line plots and stem-and-leaf diagrams |
What is the best method of showing intervals of data values? | Histograms |