COHP 350 ssignment 4 Name 1. A study is run to estimate the mean total cholester

Question

COHP 350 ssignment 4 Name 1. A study is run to estimate the mean total cholesterol in children 2-6 years of age. Asample of 9 participants is selected and their total cholesterol levels are measured as follows: 185 225 240 196 175 180 194 147 223 Generate a 95% confidence interval for the true mean total cholesterol levels in children. 2. In a clinical trial is planned to compare an experimental medication designed to lower blood pressure to a placebo. Before starting the trial, a pilot study is conducted involving participants. The objective of the study is to assess how systolic blood pressure changes over untreated. systolic blood pressures are measured at baseline and again 4 weeks later. Compute a 95% confidence interval for the differences in blood pressures over 4 weeks. Baseline 4 Weeks Difference (4 Weeks Baseline) 120 122 145 142 130 135 158 160 152 155 143 140 126 130 121 120 115 124 135 130

Explanation / Answer

Confidence Interval
CI = x ± t a/2 * (sd/ Sqrt(n))
Where,
x = Mean
sd = Standard Deviation
a = 1 - (Confidence Level/100)
ta/2 = t-table value
CI = Confidence Interval
Mean(x)=196.1111
Standard deviation( sd )=29.0019
Sample Size(n)=9
Confidence Interval = [ 196.1111 ± t a/2 ( 29.0019/ Sqrt ( 9) ) ]
= [ 196.1111 - 2.306 * (9.667) , 196.1111 + 2.306 * (9.667) ]
= [ 173.818,218.404 ]

Interpretations:
1) We are 95% sure that the interval [173.818 , 218.404 ] contains the true population mean
2) If a large number of samples are collected, and a confidence interval is created
for each sample, 95% of these intervals will contains the true population mean  

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