Analyzing and Representing Data: Tips and Tricks

• Have students collect data about topics that interest them. Data gathered by and about students are likely to hold their interest.
• Be sure students arrange the data in either ascending or descending order before seeking to find the median. Finding the middle point before ordering the data is a common mistake.
• An easy way to find the median is to order the data first and then count from each end of the data to the middle number or middle two numbers.
• If students are asked to find the mean without using calculators, the data sets should be kept relatively small. When asked to find the mean for large data sets, students should have access to calculators or computers.
• When all the outliers are greater than the other data points, the mean is greater than it would be without those outliers. Similarly, if all the outliers are less than the other data points, the mean is less than it would be without those outliers.
• When students encounter an outlier, ask them to reexamine that data point to see if a mistake was made or to see if they can explain why the outlier occurred.
• Before starting a box-and-whisker plot, ordering the data or making a stem-and-leaf plot makes finding the median and quartiles easier.
• Having your students find a graph in a newspaper or a magazine article and then having them write about it gives you the opportunity to informally assess their understanding of the graph.