A random sample of 114 lightning flashes in a certain region

A random sample of 114 lightning flashes in a certain region resulted In a sample average radar echo duration of 0.78 sec and a sample standard deviation of 0.38 sec. Calculate a 99% (two-sided) confidence interval for the true average echo duration fi. (Round your answers to two decimal places.) Interpret the resulting interval. We arc 99% confident that the true population mean lies below this interval. We are 99% confident that this interval does not contain the true population mean. We are 99% confident that the true population mean lies above this Interval. We are 99% confident that this interval contains the true population mean. You may need to use the appropriate table in the Appendix of Tables to answer this question.

Solution

4th option i.e.

we are 99% confident that this interval contains the true population mean.

	n	114
	x bar	0.78
	s	0.38
	sem	0.03559
	99% z	2.58
Margin of error	0.091823
Confidence int LB	0.688177
	Ub	0.81559