PRACTICE QUESTIONS ON MEAN FOR UNGROUPED DATA

Question 1 :

In a week, temperature of a certain place is measured during winter are as follows 26^oC, 24^oC, 28^oC, 31^oC, 30^oC, 26^oC, 24^oC. Find the mean temperature of the week.

Solution :

Mean temperature 

=  Sum of all temperature / Number of terms

=  (26 + 24 + 28 + 31 + 30 + 26 + 24) / 7

=  189/7

=  27

Hence the mean temperature is 27 ^oC.

Question 2 :

The mean weight of 4 members of a family is 60 kg. Three of them have the weight 56 kg, 68 kg and 72 kg respectively. Find the weight of the fourth member.

Solution :

Let "x" be the weight of fourth member.

Mean weight of 4 members  =  60 kg

(56 + 68 + 72 + x)/4  =  60

196 + x  =  60(4)

x  =  240 - 196

x  =  44 kg

Hence the required weight of fourth member is 44 kg.

Question 3 :

In a class test in mathematics, 10 students scored 75 marks, 12 students scored 60 marks, 8 students scored 40 marks and 3 students scored 30 marks. Find the mean of their score.

Solution :

Number of students scored 75 marks  =  10

Number of students scored 60 marks  =  12

Number of students scored 40 marks  =  8

Number of students scored 30 marks  =  3

  =  [10(75) + 12(60) + 8(40) + 3(30)] / (10 + 12 + 8 + 3)

  =  (750 + 720 + 320 + 90) / 33

  =  1880/33

  =  56.96

Question 4 :

In a research laboratory scientists treated 6 mice with lung cancer using natural medicine. Ten days later, they measured the volume of the tumor in each mouse and given the results in the table

Solution :

  =  (145 + 148 + 142 + 141 + 139 + 140) / 6

  =  855/6

  =  142.5 mm³

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