20. O 0.270.69 points I Previous Answers MintroStat8 7.E.505.XP My Notes Ask You
ID: 3254327 • Letter: 2
Question
20. O 0.270.69 points I Previous Answers MintroStat8 7.E.505.XP My Notes Ask Your Teacher Dual-energy X-ray absorptiometry (DXA) is a technique for measuring bone health. One of the most common measures is total body bone mineral content (TBBMC). A highly skilled operator is required to take the measurements. Recently, a new DXA machine was purchased by a research lab and two operators were trained to take the measurements. TBBMC for eight subjects was measured by both operators. The units are grams (g). A comparison of the means for the two operators provides a check on the training they received and allows us to determine if one of the operators is producing measurements that are consistently higher than the other. Here are the data: Subject Operator 2 3 4 5 6 1.328 1.339 1.074 1.225 0.938 1.008 1.180 1.286 1.323 1.322 1.073 1.233 0.934 1.019 1.184 1.304 (a) Take the difference between the TBBMC recorded for Operator 1 and the TBBMC for Operator 2. (Use Operator 1 minus Operator 2. Round your answers to four decimal places.) Describe the distribution of these differences using words The distribution is uniform. O The distribution is left skewed. O The distribution is Normal. O The distribution is right skewed. O The sample is too small to make judgments about skewness or symmetry.Explanation / Answer
hence Xbar=-0.0017
s=0.0109
b) t=-0.4542
degree of freedom =n-1=7
p value =0.6635
c) for 95% confidence interval and 7 degree of freedom t=2.3646
hence 95% confidence interval =sample mean -/+ t*std errror =-0.0109 ; 0.0074
operator 1 operator 2 difference(d) 1 1.328 1.323 0.005 2 1.339 1.322 0.017 3 1.074 1.073 0.001 4 1.225 1.233 -0.008 5 0.938 0.934 0.004 6 1.008 1.019 -0.011 7 1.18 1.184 -0.004 8 1.286 1.304 -0.018 mean -0.0017 std deviaition 0.0109 sample size 8.0000 std error= std dev/(n)^(1/2) 0.0039 t stat= (d)/std error -0.4542 p value = 0.6635Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.