Correlation and Causation

Using Chi-Square to Test Data
The chi-square test is a statistical tool that uses the chi-square distribution to test a hypothesis. It is important to note, however, that there are actually three kinds of chi-square tests, the use of which depends on the hypothesis being tested and the gathered data. If a researcher wants to know whether a set of data available was gathered from a normal population, then he can use the chi-square goodness of fit method. It is used to analyze one nominal variable categorized into two or more values variable, such as in the case of Shital Parikh and Lindsay WilsonADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1542/peds.2010-0333", "ISBN" : "1098-4275 (Electronic)\\r0031-4005 (Linking)", "ISSN" : "0031-4005", "PMID" : "20603257", "abstract" : "PURPOSE: Car seats should be used to prevent injury or death in children during motor vehicle crashes. When used improperly or for unintended purposes, car seats can place children at risk for injury or death. The objective of this article is to describe patterns of hazardous use of car seats outside the car for infants (<1-year-olds) in the United States from 2003 to 2007. METHODS: The National Electronic Injury Surveillance System of the US Consumer Product Safety Commission database was accessed to obtain information regarding car seat-related injuries treated in emergency departments from 2003 to 2007. Injuries sustained during motor vehicle crashes were excluded. Demographic data, type of injury, body location, disposition, injury circumstances, and other pertinent information were extracted and analyzed. RESULTS: An estimated 43 562 car seat-related injuries were treated in emergency departments from 2003 to 2007. This national estimate was based on a weighted sample of 1898 infants. The average age of these infants was 4.07 +/- 2.73 months, 62.4% of the injuries occurred in infants younger than 4 months, and 54.4% occurred in boys. Of these injuries, 49.1% occurred at home, 8.4% of the infants had to be hospitalized, and 84.3% of the infants suffered a head injury. The most common mechanisms of injury were infants falling from car seats, car seats falling from elevated surfaces, and car seats overturning on soft surfaces. CONCLUSIONS: Injury-prevention efforts should be focused on eliminating hazardous use of car seats outside the car. Caregivers should be cautioned against the placement of car seats on elevated or soft surfaces.", "author" : [ { "dropping-particle" : "", "family" : "Parikh", "given" : "Shital N", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilson", "given" : "Lindsay", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Pediatrics", "id" : "ITEM-1", "issue" : "2", "issued" : { "date-parts" : [ [ "2010" ] ] }, "page" : "352-357", "title" : "Hazardous use of car seats outside the car in the United States, 2003-2007.", "type" : "article-journal", "volume" : "126" }, "suppress-author" : 1, "uris" : [ "/documents/?uuid=43420a62-b932-47b7-9497-492e9c94e793" ] } ], "mendeley" : { "formattedCitation" : "(2010)", "plainTextFormattedCitation" : "(2010)", "previouslyFormattedCitation" : "(2010)" }, "propert...