PHY138 - Special Topic: Error Analysis - November 1, 2006

In-Class Questions

Here are today's clicker questions.

DH's method for measuring the time for 5 oscillations

About 50% of the class answered C: that I should have started and stopped the timing when the pendulum was at its maximum amplitude. This is not correct: starting the stopping when the pendulum swings through the vertical is the most precise way to do this measurement.

About 30% of the class answered correctly B: I should have counted "zero" when I started the watch. By starting the count with "one" is was actually measuring the time for 4 oscillations.

Probability that a measurment is within a standard deviation of the mean

After Dr. Harlow's big hint, almost all of you answered this correctly.

Estimating the Error in Repeated Measurements

About 60% of the class answered correctly with B: 0.05 s. This is the value that best accounts for the observed spread of values. Immediately after this question we calculated the standard deviation of the values and found it was 0.06 s.

Other Class Materials

Here is a pdf of the PowerPoint on the side screens.
And here is today's journal.