A key hospital outcome measure of clinical performance is length of stay (LOS) - that is, the number of days a patient is hospitalized. For patients at one hospital with acute myocardial infarction (heart attack), the length of stay over the past four years has consistently decreased. The hospital also has data for various treatment options such as the percentage of patients who received aspirin upon arrival and cardiac medication for left ventricular systolic dysfunction (LVSD). The data are as follows:

Year	Average LOS	Aspirin on arrival	LVSD medication
2007	4.34 days	92%		91%
2008	4.14 days	96%		95%
2009	4.12 days	98%		97%
2010	4.16 days	100%		98%

Calculate descriptive statistics for the data. Do not round intermediate calculations. Round your answers to four decimal places.

Descriptive Statistics: LOS, Aspirin, LVSD
		Standard	Standard
Variable	Mean	Error	Deviation	Minimum	Median	Maximum
LOS
Aspirin
LVSD

Calculate correlations for the data. Do not round intermediate calculations. Use a minus sign for negative values, if any. Round your answers to three decimal places.

Correlations: LOS, Aspirin, LVSD
	LOS	Aspirin
Aspirin
LVSD

Choose the correct graph showing the LOS as a function of the Aspirin on arrival.

The correct graph is

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