From the following article: a) Explain the particular statistical method(s) used

Question

From the following article:

a) Explain the particular statistical method(s) used.

b) Explain how the particular statistical method(s) is/are applied.

The Accuracy and Precision of Third Molar Development as an Indicator of Chronological Age in Hispanics According to the I.N.S., adults are defined as indiv REFERENCE: Solari AC, Abramovitch K. The accuracy and pre- dua s who cision of third molar development as an indicator of chronological have reached their 18 birthday. Individuals less than 18 years of age age in Hispanics. J Forensic Sci 2002:47(3): 531-535 are defined as juveniles. Legal consequences differ for adult de- ainees versus juvenile detainees. The stages of tooth mineraliza ABSTRACT: The accuracy and precision of chronological age on based on radiologic, distinguish stages of tooth formation estimation based on the stages of third molar tooth development was can be used to estimate chronological age in young persons. Min tudied in a sample of 679 radiographs from individuals ofHispanic cer et al. (3) scored the radiologic, mean ages of third molar de origin. The age range was 14.0 to 25.0 years. Eight raters from the University of Texas Health Science Cente at Houston Denta velopmental stages in a Caucasian population according to the Branch evaluated the radiographs according to Demirjian's developmental stages of tooth formation as proposed by Demirjian schematic definitions of crown and root formation. The objective of et al. (8). The purpose of this study was to evaluate the chronology his study was to evaluate the chronology of third molar develop of third molar developmen n Hispanics following the stages a n Hispanics following the protocol of a previous study. men formation as described by Demirjian et al. (8) Within the Hispanic population, the rate of male third molar deve is greater than that of female third molar development for opment en stages of crown-root formation. Also within this Hispanic pop Material and Methods ulation sample, the rate of maxi ary third molar development is ahead of mandibular third molar development. The mean absolute Panoramic radiographs from 679 Hispanic individuals with difference between chronological age and estimated age was t3.0 known age and gender were selected for the study. There were 395 years in females and 2.6 years in males. females and 284 males. Panoramic radiographs were available for for the remaining 5%, periapical films were 95% of the sample KEYWORDS: forensic science, third molar, Hispanic population used chronological age, panoramic radiographs, tooth formation The identification of ethnicity was made according to the patient family name, and/or demographic information presen n the pa The accuracy of determining chronological age from tooth de tient charts that could confirm Hispanic ethnicity e paren. velopment (ie dental aging) is not uniform from birth to adult name). Radiographs with major variations in tooth eruption or hood. The best precision and accuracy for age estimation from tooth morphology were not selected. The population ranged in age tooth development is achieved when individual growth is rapid and from 14 and 25 years. The mean ages for males and females were many teeth are under development (1). After age 14, estimation be- 17.3 years and 17.7 years, respectively. One hundred radiographs were assigned for each observer. Ra comes more difficult, since most of the den on is completely de- diographs were coded to ensure that the observers were blind to oped. Only the developing third molars remain for use in age ve gender, name and age of the patients. estimation (2). However, the third molar is frequently the most on with respect to size, (3-5) time of The observers scored the stage of third molar development using variable tooth in the den formation and time of eruption (6) the eight-grade scheme developed by Demirjian and coworkers In the United States of America, the Hispanic populationis grow 8,9). This was done by following the descriptive wr en criteria for each stage and by comparing the radiographs with representa ng rapidly. According to the Census Bureau, Hispanics wi surpass African Americans as the largest U.S. minority group by 2005 7) tive sketches of each stage (Fig. 1) But along with th s increase in immigration is the problem of pro- Difficulties may be greater when estimating with precision n order to achieve higher accuracy in defining sing individuals with falsified immigration documents such as stages "F" or "G their passports or birth records. The problem of illegal immigration the stages of development towards apexification, two stages were added, F1 and Gl, making ten stages of crown and root formation s magnified in states that share a common border with Mexico. In For every patient, four measurements were scored. This made it many ways, individuals with false or improper documentation are possible to also evaluate intra and inter-arch synchrony. The results detained by the Immigration and Naturalization Service (.N.S.) of and analyses were tabulated separately for each gender. If the third he United States Department of Justice, for possible deportation as letter code "N". This was was scored molar was not present done to estimate the frequency of missing third molar de Clinical Assistant Professor and Associate Professor, Dental Branch, Uni ment. When the third molar had atypical anatomy. was scored as versity of Texas-Health Science Center at Houston, 6516 M.D. Anderson Blvd U". Whenever there was a disparity in the same tooth rated by two Suite 1.072, Houston, TX. or more observers, the earliest formation stage was chosen. Received 21 Aug. 2001 accepted 7 Sept. 200 53 00 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959 Copyright 2002 by ASTM International

Explanation / Answer

a). Statistical methods which are used here for estimating the chronological age by studying the stages of third molar tooth development.

-Descriptive statistics used to get the idea about the data and subgroups in data.descriptive statistics involves measurement of Mean, Mode, Median, Percentile, skewness, kurtosis, standard deviation. Here in paper mean age for each subgroup for each stage of tooth development is displayed.

-Another statistics tool is percentile distribution of development stages.

-Cross tabulation of mexillary intra arch synchrony for males and females

- Concordance of males and females respectively

2). - Mean age for each subgroups

Data divided into male and female then maxillary and mandibular. By calculating the mean age of these subgroups and displayed in table found that male have less age than female in the third molar development. Also maxillary have less age than and mandibular in both genders.

-percentile distribution of development stage of the third molar with age span shows the variation of stages at age span in both genders. By using this here calculated the probability of male and female to be less than 18 years during different stages of development. And found that probability of less than 18 years age for female less than male in F1,G,G1 stages.

- percentile distribution of ages through the 15th,25th,50th 75th and 90th percentile follows the logical distribution pattern horizontally and vertically.

-cross tabulation is done for the subgroups (maxillary and mandibular) to intra ach synchrony for males and for females.

-concordance state that in maxilla male and female 83% and 84% respectively while mandibular have 78% and 87% concordance for male and female respectively.It shows how strong agreement between two variables hispanic age and third molar tooth development. As we can see in both maxillary and mandibular female have high concordance.

-Finally, validation has been done by analysis of absolute accuracy(estimated age - true age).

Absolute accuracy distribution shows that male have +3 years and female have +2.6 years disparity from true age.

Standard deviation of absolute accuracy for each group male and female is same 1.2

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