The distribution of the heights of 50 children are given. If the mean height for the distribution is 117.8 cm, then find x1−f1. Height110115x1120121125Numberofstudents6814f143
103
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Solution
The correct option is A 103 xififixi11066601158920x11414x1120f1120f112144841253375Total∑fi=35+f1∑f1x1=2439+14x1+120f1
Given,∑fi=50 ⇒35+f1=50⇒f1=15 We know that, ¯x=∑x1fi∑fi ⇒117.8=2439+14x1+120f150⇒5890=2439+14x1+120×15[∵f1=15]⇒5890−4239=14x1⇒1651=14x1∴x1=117.93≈118 x1−f1=118−15=103