RD Chapter 7 Statistics Ex 7.5 Solutions
Question - 11 : - Find the mean, median and mode of the following data:
Answer - 11 : -
Let assumed mean (A) =175
(i) Here N = 25, N/2 = 25/2 = 12.5 or 13 which lies in the class 150-200
l= 150, F= 10, f= 6, h = 50
Question - 12 : - A student noted the number of cars passing through a spot on a road for 100 periods each of 3 minutes and summarised it in the table given below. Find the mode of the data.
Answer - 12 : -
We see that class 40-50 has the maximum frequency
∴ It is a modal class
Answer - 13 : - Let assumed mean (A) = 135
Question - 14 : - 100 surnames were randomly picked up from a local telephone directory and the frequency distribution of the number of letters in the English alphabets in the surnames was obtained as follows:
Determine the median number of letters in the surnames. Find the mean number of letters in the surnames. Also, And the modal size of the surnames.
Answer - 14 : - Let Assumed mean (A) = 8.5
(i) Here N = 100, N/2 = 100/2 = 50 which lies in the class 7-10
Here l = 7, F = 36, f= 40, h = 3
Answer - 15 : -
Let assumed mean A = 70
(i) Here N = 50, then N/2 = 50/2 = 25 which lies in the class 60-80
∴ l= 60, F= 24, f = 12 , h = 20
Question - 16 : - The following data gives the distribution of total monthly household expenditure of 200 families of a village. .Find the modal monthly expenditure of the families. Also, find the mean monthly expenditure:
Answer - 16 : -
(i) We see that the c ass1500-2000 has maximum frequency 40
∴ It is a modal class
Here l = 1500, f = 40 , f1 = 24 , f2 = 33 , h=500
Question - 17 : - The given distribution shows the number of runs scored by some top batsmen of the world in one-day international cricket matches.
Find the mode of the data.
Answer - 17 : -
We see that class 4000-5000 has the maximum frequency18
∴It is a modal class
Question - 18 : - The frequency distribution table of agriculture holdings in a village is given below:
Find the modal agriculture holdings of the village.
Answer - 18 : - Here the maximum class frequency is 80,
and the class corresponding to this frequency is 5-7.
So, the modal class is 5-7.
l (lower limit of modal class) = 5
f1 (frequency of the modal class) = 80
f0 (frequency of the class preceding the modal class) = 45
f2(frequency of the class succeeding the modal class) = 55
h (class size) = 2
Hence, the modal agricultural holdings of the village is 6.2hectares.
Question - 19 : - The monthly income of 100 families are given as below:
Answer - 19 : - In a given data, the highest frequency is 41, whichlies in the interval 10000-15000.
Here, l = 10000,f1 = 41, f0 = 26,f2 =16 and h = 5000
