Question

Complete the table below indicating where true positive, false positive, true negative and false negatives occur. Also indicate where the Type I & Type II errors occur.

	Population Result
Sample Result	True difference exists	No difference exists
Study shows difference
Study shows no difference

Question 8: Using the table below calculate the negative predictive value, positive predictive value, sensitivity and specificity values.

		Gold Standard
		+	-	Total
Test Result	+	70	35	105
	-	20	275	295
	Total	90	310	400

What does a negative likelihood ratio of 0.3 mean?

What does a positive likelihood ratio of 6.3 mean?

Answer 1

	Population Result
Sample Result	True difference exists	No difference exists
Study shows difference	true positive	false positive(type I)
Study shows no difference	false negative(type II)	true negative

8)

negative likelihood ratio of 0.3 means that proportion of detecting negative result among condition(gold standard) to proportion of detecting negative result among unconditioned(not gold) is 0.3

positive likelihood from above: =(20/90)/(275/310)=0.3

positive likelihood ratio of 0.3 means that proportion of detecting positive result among condition(gold standard) to proportion of detecting positive result among unconditioned(not gold) is 0.3

positive likelihood from above: =(70/90)/(35/310)=6.9