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Bulbs are packed in cartons each containing 40 bulbs. Seven hundred cartons were examined for defective bulbs and the results are given in the following table : `{:("Number of defective bulbs"," 0 1 2 3 4 5 6 More than 6"),("Frequency","400 180 48 41 18 8 3" " 2"):}` One carton was selected at random. What is the probaility that it has (i) no defective bulbs ? (ii) defective buble from 2 to 6 ? (iii) defective bulbs less than 4 ? |
Answer» 700 carton were examined for defective bulbs. One carton was selected at random. (i) Let `E_(1)` be the event that selected carton has no defective bulb. We see that the number of times the event happened = 400 `:." P"(E_(1))=("Number of trials in which the event happened")/("Total number of trials")=(400)/(700)=(4)/(7)` (ii) Let `E_(2)` be the event that selected carton has defective bulbs from 2 to 6. We see that the number of times the event happened `=48+41+18+8+3=118` `:." P"(E_(2))=("Number of trials in which the event happened")/("Total number of trials")=(118)/(700)=(59)/(350)` (iii) Let `E_(3)` be the event that selected carton has defective bulbs less than 4. We see that the number of times the event happened `=400+180+48+41=669` `:." P"(E_(3))=("Number of trials in which the event happened")/("Total number of trials")=(669)/(700)` |
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