Ultrasound (US) is one of many experimental treatments used to shorten the heati

Question

Ultrasound (US) is one of many experimental treatments used to shorten the heating time for soft tissue injuries. In an experiment to gauge the efficacy of this treatment for knee injuries seven subjects with recent knee injuries were enrolled in a trial. The range of motion (in degrees) of the joint was measured first. After a prescribed (US) treatment the range of motion was measured again. Table 1 below contains the pre and post treatment responses from each of these subjects. A) Enter the differences (computed Post - Pre) in the empty cells in the lower table row. B) The 99% confidence interval for the true average difference in knee extension after versus before US treatment is: low: degrees to High: degrees C) Based on the results of this study we can conclude that:

Explanation / Answer

a.

d = ( di/n ) =-34.5/7=-4.929

b.

Confidence Interval
CI = d ± t a/2 * (Sd/ Sqrt(n))
Where,
d = di/n
Sd = Sqrt( di^2 – ( di )^2 / n ] / ( n-1 ) )
a = 1 - (Confidence Level/100)
ta/2 = t-table value
CI = Confidence Interval

Pooled Sd( Sd )= Sqrt [ 1742.77- (-34.5^2/7 ] / 6 = 16.19
Confidence Interval = [ -4.929 ± t a/2 ( 9.347/ Sqrt ( 7) ) ]
= [ -4.929 - 3.707 * (6.119) , -4.929 + 3.707 * (6.119) ]
= [ -27.613 , 17.756 ]

X Y X-Y (X-Y)^2 51.7 29.8 21.9 479.61 38.4 58.1 -19.7 388.09 35.4 64.3 -28.9 835.21 41 41.9 -0.9 0.81 35 40.8 -5.8 33.64 42.3 44.4 -2.1 4.41 40.9 39.9 1 1 -34.5 1742.77

Related Questions

Navigate

• Browse (All)
• Browse U
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.