estimate the number of person whose income are between rupees 400 and rupees 500 from the table given below
income in Rupees. no. of person
below 200. 120
200-400. 145
400-600. 200
600-800. 250
800-1000. 150
Answers
Answer:
Question 1:
The following table shows the number of students and the time they utilized daily for their studies. Find the mean time spent by students for their studies by direct method.
Time (hrs.) 0 - 2 2 - 4 4 - 6 6 - 8 8 - 10
No. of students 7 18 12 10 3
ANSWER:
Class
(Time in hours) Class Mark
xi Frequency
(Number of students)
fi Class mark × Frequency
xifi
0 - 2 1 7 7
2 - 4 3 18 54
4 - 6 5 12 60
6 - 8 7 10 70
8 - 10 9 3 27
∑fi=50 ∑xifi=218
Mean = ∑xifi∑fi
=21850
= 4.36 hours
Hence, the mean time spent by students for their studies is 4.36 hours.
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Question 2:
In the following table, the toll paid by drivers and the number of vehicles is shown. Find the mean of the toll by 'assumed mean' method.
Toll (Rupees) 300 - 400 400 - 500 500 - 600 600 - 700 700 - 800
No. of vehicles 80 110 120 70 40
ANSWER:
Class
(Toll in rupees) Class Mark
xi di = xi − A Frequency
(Number of vehicles
fi Frequency × deviation
fi × di
300 - 400 350 −200 80 −16000
400 - 500 450 −100 110 −11000
500 - 600 550 = A 0 120 0
600 - 700 650 100 70 7000
700 - 800 750 200 40 8000
∑fi=420 ∑fidi=−12000
Required Mean = A+∑fidi∑fi
=550−12000420
= 550 − 28.57
= Rs 521.43
Hence, the mean of toll is Rs 521.43.
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Question 3:
A milk centre sold milk to 50 customers. The table below gives the number of customers and the milk they purchased. Find the mean of the milk sold by direct method.
Milk Sold (Litre) 1 - 2 2 - 3 3 - 4 4 - 5 5 - 6
No. of Customers 17 13 10 7 3
ANSWER:
Class
(Milk sold in litres) Class Mark
xi Frequency
(Number of customers)
fi Class mark × Frequency
xifi
1 - 2 1.5 17 25.5
2 - 3 2.5 13 32.5
3 - 4 3.5 10 35
4 - 5 4.5 7 31.5
5 - 6 5.5 3 16.5
∑fi=50 ∑xifi=141
Mean = ∑xifi∑fi
=14150
= 2.82 litres
Hence, the mean of the milk sold is 2.82 litres.
Answer:
Step-by-step explanation:
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