In-class Exercise

There are many ways that this data could be analyzed and classified. Some options being:

• Create a plot such as a stacked bar graph to visualize and compare data side by side
• Find averages for each set of data for each gender to compare
• Create a scatter plot of all data

With the data we could find the weight by sex, balloon length by sex, baloon length compared to weight. We could also calculate the average, standard deviation or mode for the given data set. Constructing a graph or chart based upon the data to show a comparison of the variables would make the data visually easier to analyze.

• Install R and Rcmdr.
• Refer to R Commander Installation Notes for details: http://socserv.socsci.mcmaster.ca/jfox/Misc/Rcmdr/installation-notes.html
• Import the data:
  • In Rcmdr. under “Data” menu “Import data” from “text file”
  • Set the “Field Separator” to “Commas”.
  • Navigate to the CSV file and select it.
  • Click the “Edit data set” button to open the data set in a window.
  • Make a note of all outliers (to put in the legend of the figure).
  • Click on the number of each row with an outlier, then right-click and “Delete current row”.
  • Click OK to save edited data set.
• Under “Graphs” choose “Scatterplot matrix...”
  • Select all three variables.
  • Click “Plot by groups”, select Gender, and click OK.
  • Click “Options” and select the checkbox for Least-squares line and click OK.
  • Check for outliers and repeat as necessary.
• Each student independently choose one pair of variables to report in a scatter plot
  • Choose independent and dependent variables
  • Click “Plot by groups”, select Sex, and click OK.
  • Click “Options” and select the checkbox for Least-squares line and click OK.
  • Save as PDF (use this for posters)
  • Convert to PNG (use this to post at website)
  • Post as Image: write legend that includes title, description, and reports outliers.
  • (If time available, report relevant statistics, e.g. means, linear regression, or one-way ANOVA)

GIYF and here is a book for additional assistance: https://stellmack.dl.umn.edu/sites/g/files/pua2461/f/media/_the_rcmdr_gu...

Please download this directory, unzip it, and work in your group to analyze the data: https://bcrc.bio.umass.edu/data_practice/data_practice_files.tar.gz

Introduction

In this exercise, the methods of one student’s interspecific interaction at UMass was followed by another classmate to replicate the work as accurately as possible. Four different images of a species of yellow flowers were taken and observed. The images were then arranged in a panel with four labeled pictures a, b, c, and d.

Observational Differences

The first difference observed between the two figures are the sizes of the figures and the sizes of the individual panels. The first figure on the top is smaller but the proportions appear to be the same as the second figure because the images do not look stretched or squeezed. The quality of the two figures is not the same as the figure on top appears to have a better quality image than the figure on the bottom. In terms of the lighting the pictures, they are similar although the first figure has more contrast between the colors of the yellow flower petals and the color of the brown center with the small clustered seeds.

In the second panel, the ruler is not measuring the same aspect of the flower. The first figure appears to be measuring the length of one yellow petal whereas panel b, in the second figure, has the ruler placed above the flower without touching it and does not cleary measure from one specific point to another. Also, more of the ruler is shown in the first figure. In panel c, the angles in which the pictures were taken are slightly different because the picture in panel c was taken as a higher viewpoint. This further affects what is visible in the background of the pictures.

Lastly, panel d does not match one another’s images. Panel d in the first figure shows two flowers without petals with leaves on stems in the background and panel d in the second figure shows multiple flowers with bright yellow petals with the ground made up of wood chips in the background.
 

Inferences and Discussion

The several differences mentioned could be a result of different factors of the environment and the methods of how the pictures were taken with a camera and composed in an art application. The proportions of the pictures were most likely discussed but the specific dimensions were not. The pixels could also be different and result in different sizes.

It is also evident that the two students did not have the same quality camera or photography skills, which contributed to the difference in image quality and frame.

In panel b, there most likely were insufficient details on what exactly to measure on the flower and whether to measure it from the side or the top of the flower. In addition, panel c shows differences on the view at which the pictures were taken as panel c in the second figure was taken more from the side as opposed to a slightly birds eye angle.

The last panel was not replicated well, which may have been caused by lack of details, confusion, or not being to find exactly what the student has originally captured. Moreover, the flowers in the first figure may have been trimmed and removed completely if they were dried out.

At first glance, the replica of the original diagram is quite accurate.  Upon further inspection, there are some noticeable differences.  The font of the text is different, so it was likely not specified.  The letters are also misplaces, for example, the C touches the bottom of the figure, whereas the B does not.  This likely means that it was done by hand.  There is a noticeable difference in leaf color in box A.  In this same box, there is a leaf from another plant overhanging the frame that is in differing orientations.  These combined observations lead me to believe that the side from which to photograph the plant was not specified.  For boxes B and C, the picture is noticeably closer to the flower in the second figure.  This could be the result of a lack of specificity, but could also be the result of measurement inaccuracies.  

Observations:

• Top figure is taken “more zoomed in”
• Bottom figure has a blue-green hue on each picture
• The labels use completely different fonts
• There is more spacing between the images in the bottom figure than the top figure
• The black backgrounds of the labels in the bottom figure are not as carefully placed into the corners as others in top figure (they are also much bigger in the bottom figure)
• In picture a of top figure, the tree is more centered in the frame than in picture a in the bottom figure
• In picture b of the top figure the focus is very clearly the  “hole” in the tree vs the bottom picture b you can see some of the background behind the tree both picture a’s were taken at different angles
• The lighting in the pictures is very different on the trees

Inferences:

• The photographer for the bottom figure may have been shorter and unable to get exact angles/correct amount of zoom on the tree
• The photographer for the bottom figure may not have realized there was a filter on their camera/didn’t use the same camera as the photographer in top figure
• There may not have been specific directions on what exact font to use for the labels/how big to make the squares
• There may not have been exact directions on how wherein the frame the subject’s should have been (ex. In the middle)
• The amount of space between images may not have been defined in the methods
• The pictures may have been taken at different times of day/in different weather and could have caused different shadows on the tree

Paragraphs:

The top and bottom figures generally look alike. However, there is quite a distinct difference in the hues of the photos. The top figure has a natural daylight hue opposed to the bottom figure which has a blue-green hue. This coloring distracts from what the images are attempting to display. This difference could have occurred under a couple conditions such as the photographer did not realize there was a filter on their camera or they did not use the same camera as the photographer did in the top figure.

Another apparent difference is the size of the objects in each image. The top figure appears to be more zoomed in/objects look larger in each of the photos than the bottom figure. This can clearly be seen when comparing photos and viewing the background. This may have been a difference because of different settings on the camera, such as the zoom being different. This also could be because the photographer in the top photo may have been taller than the photographer in the bottom photo.

Slide 22:

• Pictures in the diagram on the left are closer than the ones on the right

  • This could be for the purpose of a better look at the leaves or because the camera wasn't as good

• There is a hand in image A on the left but no hand in any other image

  • The ruler must of had to be moved, it could have been out of the picture initially because the zoom is different

• The sizing of images A and C on the right are the same while on the left photos B and C are the same

  • The camera orientation could have been different, or this organization is more appealing to look at

• The coloring appears different between the two diagrams

  • All the pictures on the left are brighter than the right

  • This could be purposeful as to make for better observation or the position of the camera could have been under a light.

  • It's possible the flash was used as well

There are quite a few differences between the diagram of images on the right versus the diagram of images on the left, one of which is that the images on the left are a lot closer up. This could be due to the zooming effect of the camera. Different cameras have different auto zooms so this could have played a role. This could be on purpose to show more observations at a closer view. This also could have had ripple effects, such as the light changing because of the angle of the picture, and the colors looking different. Also, becasue of the fact that it's a closer picture and there has to be a ruler in the picture for size, the ruler had to be moved which casues a hand to be in the picture in the figure on the left.

The first thing I noticed is that the first and second photos in the figure are in reversed positions in each of the figures, so that photo A in Figure 1 is the equivalent to Photo B in Figure 2.

Both figures include a photo of the tree taken from a distance, however in the photo in Figure 1 there is snow around the tree but not directly in front of it, while in Figure 2 there is snow all around the tree. This indicates that the photos were possibly taken at different points in time: whichever picture was taken first must have been taken either before it snowed more, or after some of the snow had melted. This photo in Figure 1 was also taken from further away than the equivalent photo in Figure 2. 

Both figures include closeup photos of a knot in the tree and a pine needle on the ground in the snow, but the closeup photos in Figure 2 include a ruler for scale, which the photos in Figure 1 do not. The labels in Figure 2 are overall smaller than the labels in Figure 1.

The black background of the labels fits much tighter around the letters in Figure 2, and the letters are also of a different font.