# Descriptive Statistics Dot Plot Box Plot More

## Descriptive Statistics

Enter your data into cells A2 through A101 (maximum of 100 data points). The dot plot for the data is displayed with blue dots. The scale is automatically adjusted. Click on the various check boxes to see the following numerical and graphical statistics displayed: Box Plot (unmodified without indicating outliers) Quartiles (Measures of Relative Standing: 5 values divide the data into four parts with the same amount of data in each part) (Note that there are multiple methods for computing quartiles Q1 and Q3. GeoGebra uses the same method used by TI-84 calculators. Rank the data and find the median of the lower half for Q1 and the median of the upper half for Q3. The median is not counted as part of either half when there is an odd number of data values.) Fences for Outliers (Dots outside the fences are outliers. Fences are 1.5 IQR below Q1 and above Q3). Measures of Central Tendency Mean: Add up the data values and divide by the number of data values (average) Median: 1/2 of ranked data is below and 1/2 of ranked data is above the median Mode: The most often occurring data value(s) Midrange: (minimum + maximum)/2 Midquartile: (Q1 + Q3)/2 Measures of Variability Range = Maximum - Minimum IQR = Q3 - Q1 MAD = sum(absolute value of mean - data)/number of data points Standard Deviation = sum(mean - data)^2/(n-1) The data that is loaded the first time that this activity is opened is the age at first inauguration of the Presidents of the United States.