Q. 4 In a retrospective study of 71 knees scanned by MRI. One of the indicators they examined was the absence of the "bow-tie sign" in the MRI as evidence of a bucket-handle or "bucket-handle type" tear of the meniscus. In the study, surgery confirmed that 43 of the 71 cases were bucket-handle tears. The cases may be cross-classified by "bow-tie sign" status and surgical results as follows: Tear Surgically Confirmed as Test result Confirmed (D) not present (D) Positive Test 38 10 (absent bow-tie design)(7) Negative Test (absent bow-tie design)(T) 5 18 (a) What is the sensitivity and specificity of testing to see if the absent bow- tie sign indicates a meniscal tear? (b) What additional information would you need to determine the predictive value of the test?

In a bumper test, three test vehicles of each of three types of autos were crashed into a barrier at 5 mph, and the resulting damage was estimated. Crashes were from three angles: head-on, slanted, and rear-end. The results are shown below. Research questions: Is the mean repair cost affected by crash type and/or vehicle type? Are the observed effects (if any) large enough to be of practical importance (as opposed to statistical significance)?  5 mph Collision Damage ($) Crash Type Goliath Varmint Weasel Head-On 700 1,700 2,280   1,400 1,650 1,670   850 1,630 1,740 Slant 1,430 1,850 2,000   1,740 1,700 1,510   1,240 1,650 2,480 Rear-end 700 860 1,650   1,250 1,550 1,650   970 1,250 1,240     (b) Fill in the missing data. (Round your table of means values to 1 decimal place, SS and F values to 2 decimal places, MS values to 3 decimal places, and p-values to 4 decimal places.)  Table of Means   Factor 2 (Vehicle) Factor 1 (Angle) Goliath Varmint…

In a bumper test, three test vehicles of each of three types of autos were crashed into a barrier at 5 mph, and the resulting damage was estimated. Crashes were from three angles: head-on, slanted, and rear-end. The results are shown below. Research questions: Is the mean repair cost affected by crash type and/or vehicle type? Are the observed effects (if any) large enough to be of practical importance (as opposed to statistical significance)?  5 mph Collision Damage ($) Crash Type Goliath Varmint Weasel Head-On 700 1,700 2,280   1,400 1,650 1,670   850 1,630 1,740 Slant 1,430 1,850 2,000   1,740 1,700 1,510   1,240 1,650 2,480 Rear-end 700 860 1,650   1,250 1,550 1,650   970 1,250 1,240     (d) Perform Tukey multiple comparison tests. (Input the mean values within the input boxes of the first row and input boxes of the first column. Round your t-values and critical values to 2 decimal places and other answers to 1 decimal place.) Post hoc analysis for…

Dr. Mackintosh believes a new olfactory therapy would be more successful in promoting weight loss among obese patients. His patients are first weighed and then randomly assigned to olfactory therapy, dance therapy, or a control condition. At the end of the three weeks, the amount of weight lost is recorded. The results indicate no significant difference in the amount of weight lost between the three conditions. If true differences existed between the conditions, but they were not detected, what kind of error occurred?