scenario/summary

6.Week_6_ConfidenceIntrvals_MATH225N1.xlsx

Confidence Interval

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t or z Confidence Interval for µ				Confidence Interval for p Proportions
	Confidence Level	0.990	Enter decimal		Confidence Level	0.950	Enter decimal
	n	27			n	329
	Mean	17.3185			Number of Successes	141
	StDev	3.4029
	pop stdev	no	Enter yes if population stdev known
			Enter No if population stdev is unknown
	SE	0.654888			Sample Proportion	0.428571
	t	2.779			SE	0.027283
	Margin of Error	1.819935			z	1.960
	Lower Limit	15.498565			Margin of Error	0.053475
	Upper Limit	19.138435			Lower Limit	0.375096
					Upper Limit	0.482046

Put values in blue cells; output or answers in YELLOW cells
Enter values starting from B5 cell
	Data
	18.4	Mean	17.3185
	16.1	Sample Standard Deviation	3.4029
	19.5
	16.5
	12.5
	17.2
	13.8
	17.9
	19.1
	9.8
	23.8
	18.7
	19.1
	15
	19.2
	17
	11.5
	15.7
	22.5
	23.7
	19.9
	17.6
	15
	17.8
	20.7
	14.2
	15.4

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Minimum Sample Size μ for population mean				Minimum Sample Size p for Proportion
	Confidence Level	0.950	Enter decimal		Confidence Level	0.920	Enter decimal
	StDev	10			Sample Proportion	0.5	If sample proportion unknown enter 0.5
	Error	3			Error	0.03	Write percentage as decimal
	z-Value	1.960			z-Value	1.751
	Minimum Sample Size	43			Minimum Sample Size	852

Empirical Rule using standard error for CONFIDENCE INTERVAL
				ANSWER
			Empirical Rule	68-95-99.7
	mean	0.43		Lower number	Upper number
	standard deviation	0	68%	0.37	0.49
	Standard error	0.06	95%	0.31	0.55
			99.70%	0.25	0.61