Research Question: How do pine needles vary in length, within and among individual trees?
Preparation: A pine tree was located and 80 dead needles were collected from the ground. Each needle was measured with a mm ruler and the length recorded. Needles were taken from groups of two connected, the longer of the two needles was measured. The data was evaluated to find the average length of pine needles from this tree, and a histogram was created.
Evaluations: When comparing the histogram to the description of normal distributions, it was found that both had a bell-shaped curve. This reaffirms that our population is average, with normally distributed length. Using statistical mean to evaluate the data collected was the most useful and accurate way to assess the data collected. The mode was also useful for making the graph of lengths of needles found, but the mean provided the average length for the needles collected, providing the ability to find "normal" needle length for a particular species. The standard deviation calculated provided a number to give the average amount of length above and under the average needle length.
Sample Size (n) = 80 pine needles
Sample Mean = 25.81 cm
Sample Variance = 4.409 cm
Standard Deviation = 0.233 cm
Standard Error = 0.426 %
95% Confidence Interval for Mean = 0.104 %
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