A random sample of 144 observations has a mean of 20, a medianof 21 and a mode of 22. The population standard deviation is knownto equal 4.8. The 95.44% confidence interval for the populationmean is .... a) 15.2 to 24.8 b) 19.200 to 20.800 c) 19.216 to 20.784 d) 21.2 to 22.8 A random sample of 144 observations has a mean of 20, a medianof 21 and a mode of 22. The population standard deviation is knownto equal 4.8. The 95.44% confidence interval for the populationmean is .... a) 15.2 to 24.8 b) 19.200 to 20.800 c) 19.216 to 20.784 d) 21.2 to 22.8
Explanation / Answer
a) 15.2 to 24.8 b) 19.200 to20.800 20 ±2.00(4.8/sqrt(144)) c) 19.216 to 20.784 d) 21.2 to 22.8