About Vivian Expertise I can answer questions on probability, distributions, statistical inference, statistical estimation, hypothesis testing, analysis of categorical data, linear regression, generalized linear regression, ANOVA, and linear mixed models. I cannot answer questions on stochastic processes.
Experience I have worked as a research assistant at the University of Michigan, Ann Arbor for two years.
Organizations American Statistical Association
Education/Credentials University of Michigan, Ann Arbor
Master of Science
I am really hoping you will be able to help me out with my question because thus far the internet has failed me!
I am doing an assignment at the moment, and the question is as follows:
"After September 11 terrorist attacks, there was an immediate and world-wide upgrade of all airline luggge screening. Assume the number of weapons discovered in airort luggage has increased 30% since the new measures were introduced. Your task is to use signal detection approach to explore the differetn ways these data might be interpreted. Design a follow up experiment to determine whether this increase represents a chan in sensitivity or a criterion change."
I am also provided with an ROC curve and a grid with hit and false alarm values for C1, C2, C3 and C4.
My problem is that I don't know how to even start this task or how to identify specific change using the ROC curve. I would very much appreciate ANY direction or help you could give me!
Thank you in advance,
Lauren.
Answer I am new to signal detection approach. I googled it and it seems to be a theory in psychology. To design an experiment, you may find that the third graph on Signal detection theory (Encyclopedia of Psychology) at http://findarticles.com/p/articles/mi_g2699/is_0003/ai_2699000316.
I did use ROC before. So I may give some input on it. After you obtain data (sensitivity/false positive rate) from different trials, you may compare their ROCs. The criteria we used are the area under the ROC curve (AUC), plot ROCs and the no-discrimination line (the diagonal line) together. You may also discuss ROC curves in terms of their changes in slopes if these changes are interesting. For details on ROC, please take a look at the section of further interpretations on receiver operating characteristic at http://en.wikipedia.org/wiki/Receiver_operating_characteristic
Please let me know whether it is helpful. It will be greatly appreciated if you could also tell me the standard answer given by the professor. Sorry for my delay! I usually answer question on Wednesdays and weekends.
