A new test for human papilloma virus {HPV}.

A study was conducted to evaluate a new test for human papilloma virus {HPV}. One hundred fifty women with HPV were compared to 500 women who did not have HPV. A total of 160 women tested positive using the new test, 125 of whom really did have HPV. You will be graded on calculations [including completion of the 2×2 table as shown in class and showing your work for calculation, your interpretations, and your answers to the other questions. Your interpretations must be specific and will be graded on accuracy, correct use of scientific terminology, professional writing style, grammar, and spelling. 1) Complete the contingency table as shown in class. (2 points) 2) How many women are in each of the following categories? {1 point) True positives: False positives: True negatives: False negatives: 3) Calculate and interpret the sensitivity of the new screening test. [1.5 points) 4) Calculate and interpret the specificity of the new screening test. [1.5 points] 5) Calculate and interpret the positive predictive value of the new screening test. [1.5 points) 6) Calculate and interpret the negative predictive value of the new screening test. [1.5 points] 7) Do you think that it would be better to use this new screening test for HPV or an older screening test with 90% sensitivity and 80% specificity. The older screening test is more expensive. Write 100-125 words supporting your position. {1 point]

Equations

Sensitivity◦Probability that someone who has the condition tests positive◦ A / (A+C)

Specificity◦Probability that someone does not have the condition tests negative◦D / (B+D)

Positive predictive value◦Probability that someone who tests positive has the condition◦A / (A+B)

Negative predictive value◦Probability that someone who tests negative does not have the condition◦D / (C+D)

Example: Ability of mammography to detect breast cancer + – Total Mammography + 275 1,000 1,275 result – 100 65,000 65,100 Total 375 66,000 66,375 275 Sensitivity = a i c = fi = 73% may = a : b = 1227755 = 22% Specificity = —d 65’000 0 d 65’000 = = 98 _ _ _ b + a! 66,000 A’ NPV – C + d – 65_100 – 993%