Statistics - grouped frequency distributions

Drawing graphs and performing calculations for grouped frequency distributions requires an understanding of class boundaries, class width and class midpoint.

Complete the worksheet.

For the "tree" data:

• Estimate the mean and standard deviation.
• Draw a histogram.
• Produce a cumulative frequency distribution and cumulative percentage distribution.
• Draw a cumulative frequency polygon or cumulative percentage polygon.
• Use the cumulative graph to estimate the median, quartiles and interquartile range.
• How would you find deciles and percentiles using the cumulative graph?

You should be able to produce all results by hand as well as by using the TI-83.

If a cumulative graph has not been drawn, then the median, quartiles, deciles, etc. can instead be estimated by an interpolation method - see the notes.