UNCERTAINTY ESTIMATES AND HYPOTHESIS ASSESSMENT g 8300 200 ss [gl
6 UNCERTAINTY ESTIMATES AND HYPOTHESIS ASSESSMENT 0 100 200 300 400 500 600 0 20 40 60 80 100 120 Mass [g] Distance [cm] 0 100 200 300 400 500 600 0 20 40 60 80 100 120 Mass [g] Distance [cm] 0 100 200 300 400 500 600 0 20 40 60 80 100 120 Mass [g] Distance [cm]
HOW DO WE DEAL WITH NOT KNOWING THE TRUE VALUE? In" alpreal situations we don 't know the true value we are looking for We need to decide how to determine the best representation of this from our measurements We need to decide what the uncertainty is in our best representation
7 HOW DO WE DEAL WITH NOT KNOWING THE TRUE VALUE? • In “all” real situations we don’t know the true value we are looking for • We need to decide how to determine the best representation of this from our measurements • We need to decide what the uncertainty is in our best representation
AN IMPLICATION OF NOT KNOWING THE TRUE VALUE We easily divided errors into precision(bias)errors and random errors when we knew what the value was The target practice picture in the next slide is an example How about if we don't know the true value? Can we, by looking at the data in the slide after this, say that there are bias errors? How do we know if bias errors exist or not?
8 AN IMPLICATION OF NOT KNOWING THE TRUE VALUE • We easily divided errors into precision (bias) errors and random errors when we knew what the value was • The target practice picture in the next slide is an example • How about if we don’t know the true value? Can we, by looking at the data in the slide after this, say that there are bias errors? • How do we know if bias errors exist or not?
A TEAM EXERCISE List the variables you need to determine in order to carry out your hypothesis assessment What uncertainties do you foresee? (Qualitative description) Are you more concerned about bias errors or random errors? What level of uncertainty in the final result do you need to assess your hy pothesis in a rigorous manner? Can you make an estimate of the level of the uncertainty in the final result? If so, what is it? If not, what additional information do you need to do this?
11 A TEAM EXERCISE • List the variables you need to determine in order to carry out your hypothesis assessment • What uncertainties do you foresee? (Qualitative description) • Are you more concerned about bias errors or random errors? • What level of uncertainty in the final result do you need to assess your hypothesis in a rigorous manner? • Can you make an estimate of the level of the uncertainty in the final result? – If so, what is it? – If not, what additional information do you need to do this?