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W 3 P —30
EEK ROBLEMS POINTS
2.Df=3 alpha=0.05 Reject H0 if X2=7.81 New Compound=25.5,41,33,25.5
Placebo=25.5,41,33,25.5 Compute x2=28.32 D. a and b
3. -1.96,1.96,0.05 0.27,0.367,0.175,3.35 D. a and b
10 points per problem. Put answers in the table:
1.RD=0.367-0.175=0.192 RR=0.367/0.175=2.097 OR=0.367/0.633 0.175/0.825=2.74
C. One can be 95% confident that the true value will between the upper and
lower limit.
1. A clinical trial is conducted comparing a new pain medication for arthritis. Participants are
randomly assigned to receive the new medication or a placebo. The outcome is pain relief within
30 minutes. The data are shown below.
Pain ReliefNo Pain Relief
New Medication4476
Placebo 21 99
Estimate the risk difference in pain relief between treatments
= 0.92
Estimate the relative risk in pain relief between treatments
= 2.097
Estimate the odds ratio in pain relief between treatments
= 2.74
The upper and lower limits of the are shown below
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____28.32____
Is there a difference in the extent of wound healing by treatment? (Hint: Are
treatment and the percent wound healing independent?) Run the appropriate test at a
5% level of significance.
df= ____3____
alpha= __0.05______
Reject Hχ20 if > ____7.81____
Compute expected frequencies
Expected Frequency = (Row Total * Column Total)/N.
Complete the expected frequencies for each cell.
Lower Limit of CI: ____0.41____
Upper Limit of CI: ___1.61_____
Based on the Confidence Interval values which of the following are true?
A.One can be 95% confident that the true value will be greater than the upper limit.
B.One can be 95% confident that the true value will be greater than the lower limit.
C.One can be 95% confident that the true value will between the upper and lower
limit.
D.a and b
2. The following data were collected in a clinical trial evaluating a new compound designed to
improve wound healing in trauma patients. The new compound is compared against a placebo.
After treatment for 5 days with the new compound or placebo the extent of wound healing is
measured and the data are shown below.
Treatment
New Compound
Placebo
Total
Treatment
New Compound (n=125)
Placebo (n=125)
0-25%
15
(25.5 )
36
( 25.5 )
51
0-25%
15
36
Percent Wound Healing
26-50% 51-75%
3732
( 41 )( 33 )
4534
( 41 )( 33 )
8266
Percent Wound Healing
26-50% 51-75%
3732
4534
76-100%
41
( 25.5 )
10
( 25.5 )
51
76-100%
41
10
Total
125
125
250
Compute χ2.
χ2=
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Is there a significant difference in the proportions of patients reporting pain relief?
Run the test at a 5% level of significance.
Reject H0 if Z < __-1.96______ or if Z > _____1.96___
alpha= ____0.05____
Based on comparing the computed χ2 to the rejection level χ2 which of the following
is (are) true?
A.We have statistically significant evidence at alpha=0.05 to show that H0 is false.
B.Treatment and percent wound healing are not independent.
C.Treatment and percent wound healing are independent.
D.a and b.
3. A clinical trial is conducted comparing a new pain reliever for arthritis to a placebo.
Participants are randomly assigned to receive the new treatment or a placebo and the outcome is
pain relief within 30 minutes. The data are shown below.
=
__0.27______
=
_____0.367___
= _____0.175___
Z = ____3.35____
Based on comparing the computed z to the rejection level z which of the follo
(are) true?
A.We have statistically significant evidence at alpha=0.05 to show that H0 is false.
B.We have statistically significant evidence at alpha=0.05 to show that there a
significant difference in the proportions of patients reporting pain relief.
C.We do not have statistically significant evidence at alpha=0.05 to show there a
significant difference in the proportions of patients reporting pain relief.
D.a and b
New Medication
Placebo
Pain Relief
44
21
No Pain Relief
76
99
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