Uncertainties are a vital part of any scientist or engineer's toolkit. This set of on-line resources
introduces how you interpret and use uncertainties.
How to work through this lesson?
Watch the short video clips in order. After each one, try out the questions to make sure that you've mastered
the key concepts.
For students enrolled in PHYS1101, once you've finished the lesson you will need to go into Wattle and
answer the pre-lab questions in this week's homework.
Probability Distribution Functions (5:32)
Questions about the Video
Question 1
Imagine that someone has given you a plot of the probability distribution function
for the likely temperature in Canberra in July. How would you work out the odds that the
temperature at a given moment in July would be below -3 degrees?
You would need to find the area under the curve, from T= -3 down to T= minus infinity. You could do
this by integrating the curve or putting it on graph paper and counting squares.
Question 2
An electric circuit produces a variable voltage, described by this probability distribution
function:
Describe in words the voltages likely to come from this circuit.
The most likely voltage is around 8-10V. Voltages of around 2V are also fairly common. Voltages between these two ranges are relatively rare - though voltages in the range 4-7V do occasionally happen.
Question 3
The intensity of light from a pulsar ranges from about 1.4W up to 10 W. Higher values are more frequently seen than lower ones. Sketch the probability distribution function of the light from this pulsar.
