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The frequency distribution of weights (in kg) of 40 persons is given below.
Weights (in kg)
30 - 35
35 - 40
40 - 45
45 - 50
50 - 55
Frequency
6
13
14
4
3
(a) What is the lower limit of fourth-class interval?
(b) What is the class size of each class interval?
(c ) Which class interval has the highest frequency?
(d) Find the class marks of all the class intervals?

Answer :

JeanaShupp

Answer: (a) 4

(b) 5

(c) 14

(d)

Class interval       Class mark

30 - 35                       [tex]\dfrac{35+30}{2}=32.5[/tex]

35 - 40                       [tex]\dfrac{35+40}{2}=37.5[/tex]

40 - 45                        [tex]\dfrac{40+45}{2}=42.5[/tex]

45 - 50                        [tex]\dfrac{45+50}{2}=47.5[/tex]

50 - 55                        [tex]\dfrac{50+55}{2}=52.5[/tex]

Step-by-step explanation:

The data of 40 persons is given as :

Weights (in kg)    Frequency

30 - 35                  6

35 - 40                   13

40 - 45                   14

45 - 50                   4

50 - 55                  3

(a)

Lower limit is the lowest number in a class interval .

So, is the lower limit of fourth-class interval (45 - 50) is 4.

(b)

Class size = Upper limit - lower limit

So, Class size of first class interval = 35-30=5

Thus , class size of each interval is 5. [ class size remains same]

(c)

Highest frequency in table = 14 which is corresponding to 40 - 45   .

Thus , 40 - 45  is the class interval has the highest frequency.

(d)

Class mark is the mid value of each class interval.

Class interval = [tex]\dfrac{(\text{Upper limit+Lower limit})}{2}[/tex]

Class interval       Class mark

30 - 35                       [tex]\dfrac{35+30}{2}=32.5[/tex]

35 - 40                       [tex]\dfrac{35+40}{2}=37.5[/tex]

40 - 45                        [tex]\dfrac{40+45}{2}=42.5[/tex]

45 - 50                        [tex]\dfrac{45+50}{2}=47.5[/tex]

50 - 55                        [tex]\dfrac{50+55}{2}=52.5[/tex]

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