ASM 275 / ASM275 LAB 2 - ACCURACY, PRECISION, AND ERROR

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ASM 275 / ASM275 LAB 2 - ACCURACY, PRECISION, AND ERROR O °' Look at the placement of the darts with respect to the green bullseye (the true value). Are the darts accurate and precise’ [4] E*planan... aw TheanmverisC boMhacourateamd precise. Answered - Correct! No attempts IeR . — , O °' Look at the placement of the darts with respect to the bultseye (the true value]. Are the darts accurate and precise* [4] The answer is A because even though the darts are all settered with respect to the bulfseye they do surround the target. So they are not precise but on average they do approximate the measurement. O °' Look at the placement of the darts with respect to the bullseye {the true value). Are the darts accurate and precise* [4] A the darts are accurate but not precise The answer is B, precise but not accurate. Amsweced-Cor«xt! No attempts IeR O °' Look at the placement of the darts with respect to the bultseye {the true value). Are the darts accurate and precise* [4] ' ' A the darts are accurate but not precise I' s{•iann•ion The answer is D, neither precise nor accurate. Amsweced-Correct! No attempts IeR Fière is a dartbaard shek ng the bulles fthe ta rget or true value) and the Iccatioro where the ciarts •ære throvm fyelloîv dote). The bottom in-lage shows a non-nal distributiori where thie horizontal axis represents thie rrieasurerrierrt value on the dartboard and the vertical arJs représente ho•z common those values are. The vertiœ I li ne la beled "Refererœ value" is directly beneath the buIlseye. This is our TRUE value th+at ue are irying to aczorately ar+d precisely +îæasure. TÏne horizontal line A Is the differenœ between the TRUE value ar+d thie MEASURED value and li ne B represents ho•z spread out the darts are. In This diag+am, Ifnes A and B repræent •Aat? [5] Reference value Value TI-ie a ns+ver is A The diflérence beb+even the true a nd rriaasureci value is accoray. In this eample accuracy Is poor. §6 Based on the a bove, which diagram represents a more precise measurement set? [5] Reference value Value A Reference value B Value B B The answer is A, precision i Efers to how clustered the diffei ent measurement attempts are. Nore clustered = less spread out. Answered - Correct! No attempts left Assigned as O • There are many ways to reduce inter-observer and intra-observer error. One way is to have the same observer take measurements at the same time of day with the same caliper What does this accomplish? Explanation The answer is B. Answered - Co rrect! No attempts left Assigned as O • What if two observers used the same measurement instrument to measure diPerent specimens. This would have what aPect? Explanation The answer is A. Using the same measurement tool would reduœ inter-observer error. O • In the next unit we spend œnsiderable time discussing sexual dimorphism, the fact that men tend to be larger than women. Does this apply to the human skull as well? This is a basic hypothesis: Males have significantly larger skulls than females. [8] To test this, you measure a sampie of male skulls and a sample of female skulls and compare the mean values to see which is larger. However, the male skulls included in your sample are from unusually small individuals. Your study suffers from which type of error? Consider the definitions above before answering Exptanaôon The answer is B. The sample selected is not appropriate and that decision will bias the results, this is systematic error that is impossible to correct for. Answered - Correct! No attempts left O °l • During the same research project you later find out that the calipers you used to measure the females skulls were not calibrated correctly. Your study suPers from: [8] Hint Incorrect. The measurement tool was defective for only part of the sample. Furthermore, you only used these calipers for females, this is systematic error and you have to redo the study. A lot of money has been wasted. The answer is B. Answered - Sorry, that is not correct. No attempts left O °’2 How could you avoid introducing the kind of error caused by faulty ? Select all that apply. I-1.i It ipI.° z n s'.•.'e rd: You can select more than one option _ A Use the same equipment for all measurements Hint Incorrect. All three answers are ways of minimizing the chances of introducing error into your data set. Answered - Sorry, you didn’t select ALL the correct answers. No attempts left What type of error would you be testing by comparing measurements recorded a couple weeks apart by the same person? _ A Inter-observer error Explanation The answer is B. Answered - Correct! No attempts left O ••4 What type of error would you be testing by comparing measurements taken by you and then a second researcher whose data you wanted to use in your study? _ B Intra-observer error Explanation The answer is A. this would reduce inter-observer error. Answered - Correct! No attempts left Based on your understanding of error and how it is measured, what COULD Observation 1 and Observation 2 represent in this equation. Select all that apply. Hint: there are two correct responses. I- ipI.° z ns'.•.'en : You can select more than one option C Observation 1 and 2 could reflect the measurement of different specimens by the same observer D Observation 1 and 2 could reflect the measurement different specimens by different observers Explanation The answer is A and B. The two observations could either be two measurements taken by the same observer days a part, or they could represent measurements of the same specimen by two different observers. Answered - Correct! No attempts left You are combining femur head data with another researcher to evaluate the sexual dimorphism of the human femur. You both measured a test case to see if your Please useehe Aria omn bobli H e ate ' 2Scm, them = 29 cm. this va'lue [10] What is the 96 error rounded to the nearest .1? I; umer”c Ars'.’,'e• [Show More]

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