I will be employing multivariate data analysis (mostly PCA & factor analysis) for toxins in floor dust samples and study their health impact from a birth cohort study of rural children. The data set is a matrix of 228 observations of 379 variables, mostly metabolite concentrations of bacterial and fungal species.<\/p>\n
The main challenge are that a lot of the concentrations are below the detection limit and that the data set is made up of some dichotomous data that cannot easily be transformed for PCA.<\/p>\n
I will be experimenting with 1\/2-LOD replacements (as a baseline only) and Kaplan-Meier treatment (better!) of censored data (see Helsel, 2005<\/a>) to replace initial zeros for non-detects with estimates.<\/p>\n Furthermore I need to study the transformation of my non-numeric data matrix (e.g., employing the Filmer-Pritchett procedure or a polychoric PCA) for proper treatment of my dichotomous variables.<\/p>\n","protected":false},"excerpt":{"rendered":" I will be employing multivariate data analysis (mostly PCA & factor analysis) for toxins in floor dust samples and study their health impact from a birth cohort study of rural children. The data set is a matrix of 228 observations of 379 variables, mostly metabolite concentrations of bacterial and fungal species. The main challenge are … Continue reading New Chemometrics Project<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[399,406,407,405],"class_list":["post-1381","post","type-post","status-publish","format-standard","hentry","category-research","tag-chemometrics","tag-initial-zeros","tag-kaplan-meier","tag-treatment"],"_links":{"self":[{"href":"http:\/\/www.nomad.priv.at\/researchblog\/index.php?rest_route=\/wp\/v2\/posts\/1381","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.nomad.priv.at\/researchblog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.nomad.priv.at\/researchblog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.nomad.priv.at\/researchblog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.nomad.priv.at\/researchblog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1381"}],"version-history":[{"count":5,"href":"http:\/\/www.nomad.priv.at\/researchblog\/index.php?rest_route=\/wp\/v2\/posts\/1381\/revisions"}],"predecessor-version":[{"id":1393,"href":"http:\/\/www.nomad.priv.at\/researchblog\/index.php?rest_route=\/wp\/v2\/posts\/1381\/revisions\/1393"}],"wp:attachment":[{"href":"http:\/\/www.nomad.priv.at\/researchblog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1381"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.nomad.priv.at\/researchblog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1381"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.nomad.priv.at\/researchblog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1381"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}