wamba
Forum Guru
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A laboratory test has a reference mean value of 20mg/dl and a standard deviation of 2. Which of the following is the range in which 95% of repeated laboratory determinations would be expected to fall?
A. 20 to 22
B. 18 to 22
C. 16 to 24
D 19 to 21
the correct answer is C. 16 to 24. Could someone tell me why please?
Tx
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| ARJ
Forum Guru
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95 percent covers two standard deviation + or -- also SD given is 2
Mean is 20
So 20--2SD =16
and 20+2SD=24
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| nisha
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Draw it out on a bell shaped curve with the center of the curve being 20, and then move over 2 SD in either direction u'll get 16 2SD below 20 and 24, 2SD above 20..
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| wamba
Forum Guru
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Got it. Tx guys
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| frank100
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Posts: 586
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yea, got it too, (c) is the answer
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