Question

You are the newly appointed assistant administrator at a local hospital, and your first project is to investigate the quality of the patient meals put out by the food-service department. You conducted a 10-day survey by submitting a simple questionnaire to the 400 patients with each meal, asking that they simply check off that the meal was either satisfactory or unsatisfactory. For simplicity in this problem, assume that the response was 1,000 returned questionnaires from the 1,200 meals each day. The results are as follows:

	NUMBER OF UNSATISFACTORY MEALS	SAMPLE SIZE
December 1	40	1,000
December 2	48	1,000
December 3	52	1,000
December 4	59	1,000
December 5	52	1,000
December 6	46	1,000
December 7	55	1,000
December 8	36	1,000
December 9	46	1,000
December 10	46	1,000
	480	10,000

a. Determine the p¯p¯ , S_p, UCL and LCL based on the questionnaire results, using a confidence interval of 95.5 percent, which is two standard deviations

P bar:

Sp:

UCL:

LCL:

b) is it statistically in control?

Answer 1

95.5% confidence interval value is =2.0

so we have substitute the 95.5 ci value

the formula is pbar+z(sp)., so in place of z we have substrituting the value 2.0