Problem and Plan
My purpose is to see if there is any relationship between the basal diameter (dbd) and the diameter at breast height (dbh) of the Waitutu Forest Sapling trees using information published by Landcare Research NZ and recorded from various measurements of alluvial and marine terraces in the Waitutu Forest between 2001-2008. I have chosen to study this as the relationship between different variables of these saplings is important for conservationists and scientists in their studies of our native forest. The Waitutu Forest houses a number of threatened species of animals and plants. It is important that this forest keeps regenerating to continue to keep these endemic species safe. The saplings are home to these animals and therefore …show more content…
The diameter at breast height is the saplings diameter measured 1.35m above forest floor. A sapling itself is classified as any young tree that is taller than 1.35m.
Using NZgrapher I am going to make a scatter graph that compares the dbd and the dbh to see if there is any relationship. From there I can add a regression line, find the equation of my model and the correlation coefficient. This will indicate how strong a relationship there is between my two variables. I can also use my data to plot a residual plot to prove that a linear model is a good fit for my data. …show more content…
This means that the bdb is good at predicting the bdh of a sapling in the Waitutu forest. I wonder however if the height of the sapling would be an even better explanatory value in predicting the breast height diameter than the basal diameter was.
Much like my previous scatter graph I can clearly see that in the graph of height vs dbh there is a positive association as when the height increases so too does the breast height diameter. This appears to be a linear relationship therefore a linear regression line is appropriate. Looking at it, it is clear that a lot of the data falls between a height range of 135-300cm, this is where the points are most highly concentrated. As we move further up the x-axis there is less overlap in points implying that there are less sapling with a greater height than a lower height. This is interesting as the same thing occured in my other graph as we moved further up the x-axis.
The equation of my regression model for this model is y=0.070203x -3.9176. This tells me that for every 1 cm the height increases the breast height diameter of the sapling tends to increase by approximately 0.07
My purpose is to see if there is any relationship between the basal diameter (dbd) and the diameter at breast height (dbh) of the Waitutu Forest Sapling trees using information published by Landcare Research NZ and recorded from various measurements of alluvial and marine terraces in the Waitutu Forest between 2001-2008. I have chosen to study this as the relationship between different variables of these saplings is important for conservationists and scientists in their studies of our native forest. The Waitutu Forest houses a number of threatened species of animals and plants. It is important that this forest keeps regenerating to continue to keep these endemic species safe. The saplings are home to these animals and therefore …show more content…
The diameter at breast height is the saplings diameter measured 1.35m above forest floor. A sapling itself is classified as any young tree that is taller than 1.35m.
Using NZgrapher I am going to make a scatter graph that compares the dbd and the dbh to see if there is any relationship. From there I can add a regression line, find the equation of my model and the correlation coefficient. This will indicate how strong a relationship there is between my two variables. I can also use my data to plot a residual plot to prove that a linear model is a good fit for my data. …show more content…
This means that the bdb is good at predicting the bdh of a sapling in the Waitutu forest. I wonder however if the height of the sapling would be an even better explanatory value in predicting the breast height diameter than the basal diameter was.
Much like my previous scatter graph I can clearly see that in the graph of height vs dbh there is a positive association as when the height increases so too does the breast height diameter. This appears to be a linear relationship therefore a linear regression line is appropriate. Looking at it, it is clear that a lot of the data falls between a height range of 135-300cm, this is where the points are most highly concentrated. As we move further up the x-axis there is less overlap in points implying that there are less sapling with a greater height than a lower height. This is interesting as the same thing occured in my other graph as we moved further up the x-axis.
The equation of my regression model for this model is y=0.070203x -3.9176. This tells me that for every 1 cm the height increases the breast height diameter of the sapling tends to increase by approximately 0.07