{
  "@type": "dcat:Dataset",
  "accessLevel": "public",
  "bureauCode": [
    "009:25"
  ],
  "contactPoint": {
    "@type": "vcard:Contact",
    "fn": "NIH",
    "hasEmail": "mailto:info@nih.gov"
  },
  "description": "Background\n          It has been recognized that replicates of arrays (or spots) may be necessary for reliably detecting differentially expressed genes in microarray experiments. However, the often-asked question of how many replicates are required has barely been addressed in the literature. In general, the answer depends on several factors: a given magnitude of expression change, a desired statistical power (that is, probability) to detect it, a specified Type I error rate, and the statistical method being used to detect the change. Here, we discuss how to calculate the number of replicates in the context of applying a nonparametric statistical method, the normal mixture model approach, to detect changes in gene expression.\n        \n        \n          Results\n          The methodology is applied to a data set containing expression levels of 1,176 genes in rats with and without pneumococcal middle-ear infection. We illustrate how to calculate the power functions for 2, 4, 6 and 8 replicates.\n        \n        \n          Conclusions\n          The proposed method is potentially useful in designing microarray experiments to discover differentially expressed genes. The same idea can be applied to other statistical methods.",
  "distribution": [
    {
      "@type": "dcat:Distribution",
      "description": "Visit the original government dataset for complete information, documentation, and data access.",
      "downloadURL": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC115224/",
      "mediaType": "text/html",
      "title": "Official Government Data Source"
    }
  ],
  "identifier": "https://healthdata.gov/api/views/f8fs-7xsp",
  "issued": "2025-07-14",
  "keyword": [
    "gene-expression",
    "microarray-analysis",
    "nih",
    "pneumococcal-infection",
    "statistical-power"
  ],
  "landingPage": "https://healthdata.gov/d/f8fs-7xsp",
  "modified": "2025-09-06",
  "programCode": [
    "009:033"
  ],
  "publisher": {
    "@type": "org:Organization",
    "name": "National Institutes of Health"
  },
  "theme": [
    "NIH"
  ],
  "title": "How many replicates of arrays are required to detect gene expression changes in microarray experiments? A mixture model approach"
}