HP 40G manual Two-Sample Z-Interval, Confidence interval for the difference between the means

Two–Sample Z–Interval

Menu name	Z–INT: ∝1– ∝2
	This option uses the Normal Z–distribution to calculate a
	confidence interval for the difference between the means of
	two populations, ∝1 – ∝2, when the population standard
	deviations, σ1 and σ2, are known.
Inputs	The inputs are:
	Field name	Definition
	x1	Sample 1 mean.
	x2	Sample 2 mean.
	n1	Sample 1 size.
	n2	Sample 2 size.
	σ1	Population 1 standard deviation.
	σ2	Population 2 standard deviation.
	C	Confidence level.
Results
	The results are:
	Result	Description
	Critical Z	Critical value for Z.
	Δ ∝ Min	Lower bound for ∝1 – ∝2.
	Δ ∝ Max	Upper bound for ∝1 – ∝2.

Inference aplet 9-17