TY  - CHAP
M1  - Book, Section
TI  - Appendix C. Answers to Exercises
A1  - Glantz, Stanton A.
Y1  - 2012
N1  - 
T2  - Primer of Biostatistics, 7e
AB  - 2-1  The  mean  is  the  sum  of  the  observations  divided  by  the  number  of  observations,  24:  965/24  =  40.2.  To  find  the  median  we  list  the  observation  in  order,  then  select  the  (50/100)(24  +  1)  =  12.5th  point,  which  is  the  average  of  the  12th  and  13th  observations,  (29  +  30)/2  =  29.5.  The  standard  deviation  is  the  square  root  of  the  sum  of  the  squared  differences  between  the  observations  and  the  sample  mean  divided  by  the  sample  size  minus  1,  29.8.  The  25th  percentile  is  the  (25/100)(24  +  1)  =  6.25.  Thus,  the  25th  percentile  is  between  the  6th  and  7th  observation,  which  we  average  to  obtain  (13  +  13)/2  =  13.  Likewise,  the  75th  percentile  is  (75/100)(24  +  1)  =  18.75,  so  we  average  the  18th  and  19th  observations  to  obtain  (70  +  70)/2  =  70.  The  fact  that  the  median  is  very  different  from  the  mean  (29.5  versus  40.2)  and  not  located  roughly  equidistant  between  the  top  and  bottom  quartile  indicates  that  the  data  were  probably  not  drawn  from  a  normal  distribution.  (If  the  data  were  symmetrically  distributed  about  the  median,  we  could  have  further  checked  for  normality  by  computing  the  2.5th,  16th,  84th  and  97.5th  percentiles  and  comparing  them  with  values  2  and  1  standard  deviations  below  and  above  the  mean,  as  described  in  Fig.  2-10.)  
SN  - 
PB  - The McGraw-Hill Companies
CY  - New York, NY
Y2  - 2024/04/16
UR  - accessbiomedicalscience.mhmedical.com/content.aspx?aid=57421297
ER  -