In a study designed to test the effectiveness of magnets for treating back pain,
ID: 3126495 • Letter: I
Question
In a study designed to test the effectiveness of magnets for treating back pain, 35 patients were given a treatment with magnets and also a sham treatment without magnets. Pain was measured using a scale from 0 (no pain) to 100 (extreme pain). After given the magnet treatments, the 35 patients had pain scores with a mean of 7.0 and a standard deviation of 2.8. After being given the sham treatments, the 35 patients had pain scores with a mean of 5.4 and a standard deviation of 2.1. Complete parts (a) through (c) below. Construct the 90% confidence interval estimate of the mean pain score for patients given the magnet treatment. What is the confidence interval estimate of the population mean mu?Explanation / Answer
Confidence Interval
CI = x ± Z a/2 * (sd/ Sqrt(n))
Where,
x = Mean
sd = Standard Deviation
a = 1 - (Confidence Level/100)
Za/2 = Z-table value
CI = Confidence Interval
Mean(x)=7
Standard deviation( sd )=2.8
Sample Size(n)=35
Confidence Interval = [ 7 ± Z a/2 ( 2.8/ Sqrt ( 35) ) ]
= [ 7 - 1.64 * (0.47) , 7 + 1.64 * (0.47) ]
= [ 6.22,7.78 ] ~ [ 6.2 , 7.8 ]