One-sample t test of Speed of Light Data
In this activity, you will be performing a one sample t-test
analysis on the velocities of light in air collected by the physicist A. A.
Michelson in 1879. These measurements were made available at the Data
and Story Library at Carnegie Mellon
University. These measurements were grouped into five trials of 20
measurements each. The numbers are in m/sec, and have had 299,000 subtracted
from them.
Because the speed of light is a physical constant, we know (to a very close approximation) the "true" value that Michelson was trying to measure. The true value of the speed of light is 299,734.5 meters per second. It is therefore possible to test the null hypothesis that the true mean = 734.5 for each of the trials separately or for all 100 determinations taken together.
In order to perform a one-sample t-test with an Excel or Text file, you need to use the applet found at www.statpoint.com. You have to manually enter the data (copying and pasting fills in the fields correctly) and then click on the t-test tab to get your results. To enter the expected value, click on "Options" under the t-test tab.
The light data collected exists in
two file types; one is in Excel
format, and one is in Text format. What was the p-value of the results using all 100 determinations as the
sample? What does the p-value
show for the t-test? Is there a statistically significant difference, indicating
a flaw in Michelson's experiment?