Maths Statistics Exercise20-1
Please Select
Q1 Find the mean of 8, 6, 10, 12, 1, 3, 4, 4.
Solution :
Q2 5 people were asked about the time in a week they spend in doing social work in their community. They replied 10, 7, 13, 20 and 15 hours, respectively. Find the mean time in a week devoted by them for social work.
Solution :
Q3 The enrollment of a school during six consecutive years was as follows: 1620, 2060, 2540, 3250, 3500, 3710, Find the mean enrollment.
Solution :
Q4 Find the mean of the first twelve natural numbers.
Solution :
Q5 (i) Find the mean of the first six prime numbers.
(ii) Find the mean of the first seven odd prime numbers.
Solution :
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Q6 (i)The marks (out of 100) obtained by a group of students in a Mathematics test are 81, 72, 90, 90, 85, 86, 70, 93 and 71. Find the mean marks obtained by the group of students.
(ii) The mean of the age of three students Vijay, Rahul and Rakhi is 15 years. If their ages are in the ratio 4 :5:6 respectively, then find their ages.
Solution :
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Q7 The mean of 5 numbers is 20. If one number is excluded, mean of the remaining
Solution :
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Q8 The mean of 25 observations is 27. If one observation is included, the mean still remains 27. Find the included observation.
Solution :
Q9 The mean of 5 observations is 15. If the mean of first three observations is 14 and that of the last three is 17, find the third observation.
Solution :
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Q10 The mean of 8 variate is 10-5. If seven of them are 3, 15, 7, 19, 2, 17 and 8, then find the 8th variate.
Solution :
Q11 The mean weight of 8 students is 45-5 kg. Two more students having weights 41-7 kg and 53-3 kg join the group. What is the new mean weight?
Solution :
Q12 Mean of 9 observations was found to be 35. Later on, it was detected that an observation 81 was misread as 18. Find the correct mean of the observations.
Solution :
Q13 A student scored the following marks in 11 questions of a question paper :
7, 3, 4, 1, 5, 8, 2, 2, 5, 7, 6.
Find the median marks.
Solution :
Q14 Calculate the mean and the median of the numbers:
2, 3, 4, 3, 0, 5, 1, 1, 3, 2.
Solution :
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Q15 A group of students was given a special test in Mathematics. The test was completed by the various students in the following time in (minutes)
24, 30, 28, 17, 22, 36, 30, 19, 32, 18, 20, 24.
Solution :
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Q16 In a Science test given to a group of students, the marks scored by them (out of 100)are
41, 39, 52, 48, 54, 62, 46, 52, 40, 96, 42, 40, 98, 60, 52.
Find the mean and median of this data.
Solution :
Q17 The points scored by a Kabaddi team in a series of matches are as follow
17, 2, 5, 27. 15. 8. 14, 10, 48, 10, 7, 24, 8, 28, 18.
Solution :
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Q18 The following observations have been arranged in ascending order. If the median the data is 47-5, find the value of x.
17, 21, 23, 29, 39, 40, x, 50, 51, 54, 59, 67, 91, 93
Solution :
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Q19 The following observations have been arranged in ascending order. If the median the data is 13, find the value of x:
3, 6, 7, 10, x, x + 4, 19, 20, 25, 28.
Solution :
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