Question 1063307: For the following data set
114 112 123 111 109 103
112 113 107 129 108 126
131 129 126 115 123 108
131 115 134 133 132 114
104 127 128 137 114 139
128 117 121 110 141 121
138 140 122 130 115 102
Table 1: Data set Exercise 1
Construct a
1. 90% confidence interval for the population mean;
2. 95% confidence interval for the population mean;
3. 99% confidence interval for the population mean;
4. What assumption do you need to make about the population of interest to construct the confidence
intervals ?
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! mean is 121.238
sd=11.080
df=41 (there were 42 observations)
t(0.95,41)=1.6829; the next is t(0.975,41) and then t(0.995,41)
90% CI=121.24+/-1.6829(11.08/sqrt(41)); Std error, the last part, is 2.95, (118.29,124.19)
95% CI=121.24+/-2.0196(11.08/sqrt(41)); SE is 3.49, (117.75, 124.73)
99% CI=121.24+/-2.7012(11.08/sqrt (41)); SE is 4.67 (116.57, 125.91)
Assumptions: data are readings of something taken using an appropriate random sample from a population that is normally distributed and the standard deviation of the sample may be used to approximate the standard deviation of the population.
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