1. Formal Lab Report Discussion
December 2017

2. Paragraph 1
Describe data (specifically refer to your data table and state values like mean, variance and standard deviation)
Describe what your variance and standard deviation values say about the validity of your results.
Use the variance and standard deviation values to determine whether the results SUPPORT or REFUTE your hypothesis.

3. Variance
Variance is the average of the squared distance from the mean of the data.
If the variance is low, then the data points are closely clustered around the mean.
If the variance is high, then the data points are farther away from the mean.
In most cases, a low variance indicates more valid results.

4. Standard Deviation
Standard deviation is the square root of the variance.
If the standard deviation is high, it means the data are widely dispersed.
If the standard deviation is low, it means the data are closely clustered.
In most cases, data with a low standard deviation is more valid than data with a high standard deviation.

5. Sample Size (number)
Sample size (or number of repeated trials) influences validity of results and is also used in calculating variance and standard deviation.
The magic number of trials to obtain maximum validity is usually 30.
In sample sizes of less than 30, it is more likely to have a high variance and standard deviation.
If the sample size is small and the variance and standard deviation are low, then, your results are good, BUT, you would need to do the experiment again with more repeated trials to be considered scientifically significant in most disciplines.

6. Accepting or rejecting the hypothesis
In science, we don’t really every PROVE or DISPROVE anything. Instead, we say our data SUPPORTS our hypothesis, or it REFUTES our hypothesis.
Scientific laws and theories are developed when results are repeated many, many times and peer reviewed by an international community of respected scientists. Therefore, the work that we do at the high school level would not meet the criteria of proving or disproving anything.

7. Paragraph 2
State the difference between APPARENT MAGNITUDE and ABSOLUTE MAGNITUDE.
Then, draw conclusions about 1) the relative DISTANCE the three stars listed in the table are from Earth based on their apparent magnitude and 2) how bright the stars ACTUALLY are based on their absolute magnitude.
Remember, stars that are CLOSER will APPEAR brighter than stars that are farther away, just like in our experiment, the luminosity of the lamp DECREASED as you moved AWAY from it.

8. Paragraph 3
We are not perfect people. Even though you got pretty good results, there are always ways to improve your experiment.
Consider ways to improve the results of this experiment that do not include “more time” or “better materials.” Even scientists with $10 million research grants would like more time and better materials!
Consider how your group worked to take measurements. Did you adjust the sensor in the same way for each distance? Were there errors in reading the measurements? Did the same person move the sensor or take the readings?
We all should do MORE TRIALS and try it in a space that allows us to move more than 3 meters away.