Qs 1) BRCA1 is a gene that has been linked to breast cancer.Researchers used DNA
ID: 2954911 • Letter: Q
Question
Qs 1) BRCA1 is a gene that has been linked to breast cancer.Researchers used DNA analysis to search for BRCA1 mutations in 169women with family histories of breast cancer. Of the 169 womentested, 27 has BRCA1 mutations. Let denote theprobability that a woman with a family history of breast cancerwill have a BRCA1 mutation.a) Find the 95% confidence interval for . Show yourcalculations. Explain what the interval means.
b) Assume that your sample of women is from a geneticallydisticnt ethnic subgroup, the population of which is only N =3000women. Compute the CI incorporating the additionalinformation.
c) Compare the two confidence intervals. a) Find the 95% confidence interval for . Show yourcalculations. Explain what the interval means. b) Assume that your sample of women is from a geneticallydisticnt ethnic subgroup, the population of which is only N =3000women. Compute the CI incorporating the additionalinformation. c) Compare the two confidence intervals.
Explanation / Answer
Given n=169, p=27/169 = 0.16 (a) Given =0.05, Z(0.025)=1.96 (check normal table) The 95% CI is p±Z*p*(1-p)/n --> 0.16 ± 1.96*sqrt(0.16*(1-0.16)/169) --> ( 0.1047, 0.2152)