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RD Chapter 7- Statistics Ex-7.2 Interview Questions Answers

Question 1 :
The. number of telephone calls received at an exchange per interval for 250 successive one-minute intervals are given in the following frequency table:
 
Compute the mean number of calls per interval.

Answer 1 :

Let assumed mean (A) = 4
 
Hence mean number of calls per interval = 3.54

Question 2 : Five coins were simultaneously tossed 1000 times, and at each toss the number of heads was observed. The number of tosses during which 0, 1, 2, 3, 4, and 5 heads were obtained are shown in the table below. Find the mean number of heads per toss

Answer 2 :

Let assumed means (A) = 3
 
Hence mean number of tosses per head = 2.47

Question 3 :
The following table gives the number of branches and number of plants in the garden of a school.
 
Calculate the average number of branches per plant.

Answer 3 :


Meannumber of branches per plant = 3.62

Question 4 :
The following table gives the number of children of 150 families in a village
 
Find the average number of children per family.

Answer 4 :

Let assumed mean (A) = 3
 
= 3 – 0.65 = 2.35
Hence mean number of children per family = 2.35

Question 5 :
The marks obtained out of 50, by 102 students in a Physics test are given in the frequency table below:
 
Find the average number of marks.

Answer 5 :