Posted by: unlikelygrad | January 31, 2010

no wonder you failed!

At my school GenChem is a requirement for all students. Thus, most incoming freshmen take Chem 1 in the fall and Chem 2 in the spring. It should not be a surprise, then, that most people who are taking Chem 1 in the spring are those who failed it the first time around. (We do have a number of students who transferred in mid-year, but these are definitely in the minority.)

I am in the middle of grading my first set of lab assignments, and it’s become glaringly obvious why many of these people failed: they can’t follow directions! The assignment was, I thought, very simple:

  1. Given a set of measurements for area and radius (created by a randomizer–everyone had a different set of data), use Excel to create a value for radius squared. Use Excel to create a series of values for pi (A/R^2).
  2. Calculate the average, standard deviation, and confidence interval for these values.
  3. Graph A vs. R^2. Use Excel to calculate a linear regression. The slope of this line should be pi.
  4. Compare the two values for pi. Tell which method you think is better, and why.

Note that I specifically told them, “If you don’t know how to use Excel, please stay after class so I can show you. Or come to my office hours.” No one asked for help. And yet, I’ve seen the following:

  • Students who must have done all the calculations on their calculator, then entered the answers into Excel. The numbers are right, but no formulae are present.
  • People graphing weird things: value of pi vs. area, radius vs. area, or (my favorite) value of pi calculated vs. measurement number
  • Graphs which are not scatter plots (line graphs are most common), some of which have no linear regression done. How did they come up with a value of pi for this? I have no idea, but it’s written below the graph.

As one of the professors said during our last meeting: “And these people are going to be designing our bridges in ten years?!! Kind of scary!”

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Responses

  1. Hey I have a good handout for walking the little dimwits through excel to plot graphs and do linear regression on excel if you need it. Its based off of a density experiment.

  2. I just graded a stack of lab reports wherein the students here demonstrated a similar inability to follow basic directions. *cue Ying hands*

  3. Thanks for the offer, Genomic Repairman. However, the students *had* a handout that walked them through making a graph and doing a linear regression.

    The fact that some of them emailed me a Word document when they were specifically told to send an Excel spreadsheet should tell you just how bright they are.

  4. see i have failed in 2nd puc can i get a seat for BBM in your coll…i m readdy to pay money


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