© 2018 JETIR August 2018, Volume 5, Issue 8 www.jetir.org (ISSN-2349-5162) Probability of Left Handers (Sinisters) in a World Population Dr. Bhavin S. Patel Assistant Professor, Applied Science & Humanities Department, Sankalchand Patel College of Engineering, Visnagar, Gujarat, India; Abstract: In the world, only about 10 % of the population is left handed and the rest of them is right handed. It is believed Sinisters (left handers) make upto 5 % to 10 % of the world population and are more likely to be on extreme poles of the intelligence scale. Left handedness is completely genetic. Being left or right handed has no other relation. Left handedness or Right handedness comes genetically from child’s father or mother or both. We seek to find the probability that the new born baby (child) is left handed or right handed in the present research paper. Keywords: Left Handers (Sinisters), Left handedness, Right handedness, World Population Introduction: Handedness is a better performance or individual preference for use of a hand, known as the dominant hand, the less preferred hand is called the nondominant hand. There are four types of handedness: Left-handedness, Right-handedness, Mixed-handedness and Ambidexterity. Left-handedness is somewhat more common among men than among women. Right handedness is most common among people. Right handed people are more skillful with their right hands when performing tasks. Studies suggest that 88-92 % of the world population is right handed. Left handedness is far less common than right-handedness. Left handed people are more skillful with their left hands when performing tasks. Studies show that approximately 10 % of the world population is left handed. Mixed-handedness is the change of hand preference between tasks. This is common in about 1 % of the population. Ambidexterity is exceptionally rare case, although it can be studied. A truly ambidextrous person is able to do any task equally well with either hand. In this research paper, though, we concentrate on common types: Left handedness and Right handedness. Left handedness is less common among people than right handedness. For left handers, International Left Hander’s Day is celebrated on August 13th every year. International Left Hander’s Day was first celebrated on August 13, 1976. It was started by Left Hander’s International. Calculation of probabilities: As it is discussed in the abstract of this paper that, Left handedness is completely genetic. It comes from child’s father or mother or both. Henceforth, if we randomly select father-mother combination, it is a random experiment. We denote right-handedness by R and left-handedness by L. In particular, we denote right handed father-mother combination by 푅푅. Same way others can be denoted by 푅퐿 i.e. right handed father and left handed mother, 퐿푅 i.e. left handed father and right handed mother and 퐿퐿 i.e. left handed father-mother combination. JETIR1808214 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 464 © 2018 JETIR August 2018, Volume 5, Issue 8 www.jetir.org (ISSN-2349-5162) The sample space for this random experiment is 푆1 = {푅푅, 푅퐿, 퐿푅, 퐿퐿} having 4 different father-mother combinations i.e. four sample points. Biologically, a baby born from any father-mother combination is either a boy or a girl who can be right handed or left handed genetically. For this experiment, the sample space is 푆2 = {퐵푅, 퐵퐿, 퐺푅, 퐺퐿}. If we select randomly any child to check whether he/she is right handed or left handed, this selection is a random experiment again. The sample space for this random experiment is 푆1 × 푆2 = 푅푅퐵푅, 푅푅퐵퐿, 푅푅퐺푅, 푅푅퐺퐿, 푅퐿퐵푅, 푅퐿퐵퐿, 푅퐿퐺푅, 푅퐿퐺퐿 { }. There are 푛 = 16 sample points. 퐿푅퐵푅, 퐿푅퐵퐿, 퐿푅퐺푅, 퐿푅퐺퐿, 퐿퐿퐵푅, 퐿퐿퐵퐿, 퐿퐿퐺푅, 퐿퐿퐺퐿 A baby born from father-mother combination, either boy or girl, is most likely to be left handed if father-mother combination is 퐿퐿 i.e. father and mother both are left handed. The sample points set for this event 퐴 is 퐴 = {퐿퐿퐵퐿, 퐿퐿퐺퐿} . Both these sample points are disjoint i.e. mutually exclusive. Using 1 1 probability theory, the probabilities of these events are calculated as 푃(퐿퐿퐵퐿) = and 푃(퐿퐿퐺퐿) = . 16 16 Therefore, the probability that the newborn baby (child) is a left hander is at least 1 = 0.0625. The probability that the newborn baby is left handed boy or girl is 16 2 1 푃(퐴) = = = 0.125. Eventually, the range of probability of the newborn baby (child) being left handed 16 8 is 0.0625 to 0.125 i.e. 6.25 to 12.5 %. This range is roughly nearer to the range 5 to 10 % which is just believed to be but has not been proved. On the other hand, a newborn baby (child) is most probably right handed if any one of the parents is right handed. The sample points set for this event 퐵 is 퐵 = {푅푅퐵푅, 푅푅퐵퐿, 푅푅퐺푅, 푅푅퐺퐿, 푅퐿퐵푅, 푅퐿퐵퐿, 푅퐿퐺푅, 푅퐿퐺퐿, 퐿푅퐵푅, 퐿푅퐵퐿, 퐿푅퐺푅, 퐿푅퐺퐿}. The probability that the newborn baby is right handed boy or girl is 12 푃(퐴) = = 0.75. Moreover, a newborn baby is right handed boy or girl even if his/her parents are both 16 left handed occur very rarely. The sample space of this event 퐶 is 퐶 = {퐿퐿퐵푅, 퐿퐿퐺푅}. The probability that the newborn baby is right handed even if both the parents are left 2 handed is 푃(퐶) = = 0.125. 16 Hence, the probability range that a newborn baby is right handed is 0.75 to 0.875 i.e. 75 to 87.5 %. The Actual Observation by Sampling: A. Sample-1 We collected data for the sample of 19 students of Standard-V from H.B.Kapadia School in Unjha. The details are as under: Standard-V, H.B.Kapadia School, Unjha Roll No. Boy or Girl (B Lefty or Righty (L Father Lefty or Mother Lefty or or G) or R) Righty (L or R) Righty (L or R) JETIR1808214 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 465 © 2018 JETIR August 2018, Volume 5, Issue 8 www.jetir.org (ISSN-2349-5162) 1 Boy R R R 2 Boy R R R 3 Boy R R RL 4 Boy R R R 5 Girl R R R 6 Boy L R L 7 Boy R R R 8 Boy R L R 9 Boy R R R 10 Boy R R R 11 Boy R R R 12 Girl R R R 13 Girl R R L 14 Boy R R R 15 Boy R R R 16 Girl L R R 17 Boy R R R 18 Boy R R R 19 Boy R R R Here RL means both Righty and Lefty. Above tabular data shows that 2 students out of 19 students are left handed. Of these 2 students, one is 2 boy and girl each. So, the probability that a randomly selected student is left handed is = 0.105 i.e. 19 10.5 % which falls in the range 6.25 to 12.5 %. B. Sample-2 We collected data for the sample of 31students of Standard-VI from NOOTAN GLOBAL SCHOOL in VISNAGAR. The details are as under: Standard-VI, NOOTAN GLOBAL SCHOOL, VISNAGAR Roll No. Boy or Girl (B Lefty or Righty (L Father Lefty or Mother Lefty or or G) or R) Righty (L or R) Righty (L or R) 1 Boy R R R 2 Boy R R R 3 Boy R R R 4 Girl L L R 5 Boy R R R 6 Boy L R R 7 Boy R R R 8 Girl R R R 9 Boy R R R 10 Girl L R R 11 Girl R R R 12 Girl R R R 13 Boy R R R 14 Boy R R R 15 Girl R R R 16 Girl R R R 17 Girl R R R JETIR1808214 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 466 © 2018 JETIR August 2018, Volume 5, Issue 8 www.jetir.org (ISSN-2349-5162) 18 Girl R R R 19 Girl R R R 20 Boy R R R 21 Boy R R R 22 Boy R R R 23 Girl R R R 24 Boy R R R 25 Boy R R R 26 Girl R R L 27 Girl R R R 28 Boy R R R 29 Boy R R R 30 Girl R R R 31 Girl R R R Above statistics show that 3 students out of 31 students are left handed from the randomly selected class 3 of the school. So, the probability that a randomly selected student is left handed is = 0.097 i.e. 9. 70 % 31 which falls in the range 6.25 to 12.5 %. C. Sample-3 This sample is quite different from the above samples. We have collected names of some greatest people of the world over. These people are left handers and they have extra ordinary intelligence power to be successful in their life irrespective of their field or profession. This sample includes the names of Mahatma Gandhi, Prime minister Narendra Modi, Millenium star Amitabh Bachchan, Sachin Tendulkar, Barack Obama, Sir Albert Einstein et al. The details of all these greatest people are given below. These people come from the range of left handers 6.25 to 12.5 %. Henceforth, we can say that the greatest people most probably have left hand as their strong hand with which they write or give extra ordinary ideas to the world by their work. These are the greatest examples of world dominance by lefties.