Module 2 Fundamental data analysis Flashcards
What two types of errors are uncertainties caused by?
Random and systematic
what are systematic errors, how are they caused, how easy are they to spot, what is their effect
They are the same every time you repeat the experiment, they shift all the values by the same amount. They may be caused by the equipment you’re using or how it’s set up. Systematic errors are really hard to spot, and they affect the accuracy of your results.
Describe random errors. How can you reduce their effect?
they’re what make the results a bit different each time you repeat an experiment. It could be that you just can’t keep controlled variables exactly the same throughout the experiment.
Repeating measurements can also reduce the effects of random errors. Using equipment with a higher resolution means that the equipment can detect smaller changes.
How do you find the uncertainty in the value of the gradient of a graph?
The uncertainty in the gradient is given by the difference between the best gradient and the worst gradient.
How do you find the uncertainty in the y-intercept of a graph?
Draw the worst lines through the uncertainty bars. The uncertainty is the difference between the best and worst intercepts vertically for an uncertainty bar
measure for angle of circle arc in radians
angle (radians) = arc length (m) / radius (m)
think L = r * (theta)
percentage uncertainty equation
percentage uncertainty = absolute uncertainty in reading * 100% / actual reading
how to calculate uncertainties when adding or subtracting quantities
when adding or subtracting quantities, you add the absolute uncertainties
how to calculate percentage uncertainty when multiplying or dividing quantities,
how to use this to find absolute uncertainty
when multiplying or dividing quantities you add the percentage uncertainties
multiply the final %uncertainty by the final quantity value to find its absolute uncertainty
how to calculate percentage uncertainty when raising a quantity to a power
how to calculate absolute uncertainty from that
when you a raise a quantity to a power n, you multiply the % uncertainty of that quantity by n,
multiply the final %uncertainty by the final quantity value to find its absolute uncertainty
how to calculate spread from range
spread = 0.5 * range
spread is the uncertainty in a reading
what is the line of worst fit and how do you calculate it
the least acceptable straight line through the data points. after you have drawn your uncertainty bars at each point. start from the bottom of the first uncertainty bar and get to top of the last uncertainty bar
