Question

A random sample of 109 lightning flashes in a certain region resulted in a sample average radar echo duration of 0.82 sec and a sample standard deviation of 0.41 sec. Calculate a 99% (two-sided) confidence interval for the true average echo duration u. (Give answers accurate to 3 decimal places.) (717 923 X) Interpret the resulting interval. o We are 99% confident that this interval does not contain the true population mean. . We are 99% confident that this interval contains the true population mean. We are 99% confident that the true population mean lies below this interval. O We are 99% confident that the true population mean lies above this interval.

Answer 1

Given that Sample mean, z=0.82 See Sample Size , n=109 x=0.01 Sam: - Sample Standard deviation, s -0.41 See Degree of freedom =109-1 = 108 99% confidance interval: s ăt tcritical in Putting the values we get - 0-1 Jordical at degree of freedom 108 And - tcritical + 2.62212 0.41 log 0.82 I 0.1029729 0.82 +262212 600 -(0770,0.3228) (0.717,0.922) anonaga So, the required 999 confidence interval for the true echo duration M is (0.717, 0.922 Ansmer