Question

Please answer all questions, show all work ofr how you figured out the answer

Question 1: The 95% confidence limits for creatine kinase enzyme activity in a level I control are 130-252 U/L. What is the standard deviation for this control?

Quesiton 2: The process of comparing consecutive laboratory values from the same patient for quality assurance purposes is termed

A. Logical consistency

B. Delta checking

C. Physiological relationship checking

D. Arithmetic checking

Question 3: A series of LDH enzyme measurements on a control serum yield the following:
Mean = 130 U/L SD = 13 U/L Assuming that the data follow a typical normal distribution, approximately 32% of the data will fall outside which of the following ranges?
A. 91-169 U/L

B. 100-150 U/L

C. 104-156 U/L

D. 117-143 U/L

Answer 1

95% C.I. =(130,252)

2MOE = 252-130

or, MOE = 122/2 =61

or, z_0.05/2 * s.d = 61

or, s.d. = 61/1.96 [ z_0.05/2 = 1.96]

= 31.122

2) The process of comparing consecutive laboratory values from the same patient for quality assurance purposes is termed as Delta checking

3) Mean = 130U/L

SD = 13U/L

Approx. 32% of the data will fall outside

(Mean - z_0.32/2 *SD , Mean + z_0.32/2 *SD)

Now, z_0.032/2 = P[Z>z]=0.16

or, z=1

The range = (130-1*13 , 130+1*13) = (117 , 143)

hence D is the correct option