Question

Question 8.
A grouped frequency table with class intervals of equal sizes using 250-270 (270 not included in this interval) as one of the class interval is constructed for the following data:
268, 220, 368, 258, 242, 310, 272, 342, 310, 290, 300, 320, 319, 304,402, 318, 406, 292, 354, 278, 210, 240, 330, 316, 406, 215, 258, 236.
The frequency of the class 370-390 is:
(a) 0
(b) 1
(c) 3
(d) 5
Answer
Question 9.
A grouped frequency distribution table with classes of equal sizes using 63-72 (72 included) as one of the class is constructed for the following data:
30, 32, 45, 54, 74, 78, 108, 112, 66, 76, 88, 40, 14, 20, 15, 35, 44, 66, 75, 84, 95, 96, 102, 110, 88, 74, 112, 14, 34, 44.
The number of classes in the distribution will be:
(a) 9
(b) 10
(c) 11
(d) 12
Answer
Question 10.
To draw a histogram to represent the following frequency distribution:

the adjusted frequency for the class 25-45 is:
(a) 6
(b) 5
(c) 3
(d) 2
Answer
Question 11.
The mean of five numbers is 30. If one number is excluded, their mean becomes 28. the excluded number is:
(a) 28
(b) 30
(c) 35
(d) 38
Answer
Question 12.
If x¯ represents the mean of n observations x1, x2, …, xn, then value of ∑ni=1(xi−x¯) is:
(a) -1
(b) 0
(c) 1
(d) n – 1
Answer
Question 13.
If each observation of the data is increased by 5, then their mean
(a) remains the same
(b) becomes 5 times the original mean
(c) is decreased by 5
(d) is increased by 5
Answer
Question 14.
Let x¯ be the mean of x1, x2, …, xn and y the mean of y1, y2, …, yn. If z is the mean of x1, x2, …. xn, y1, y2, …, yn, then z is equal to
(a) x¯+y¯
(b) x¯+y¯2
(c) x¯+y¯n
(d) x¯+y¯2n
Answer
Question 15.
If x¯ is the mean of x1, x2, …, xn, then for a ≠ 0, the mean of ax1, ax2, …, axn, x1a, x2a, …….., xna is

Answer
Question 16.
If x1¯, x2¯, ​

Answer 1

Answer:

Step-by-step explanation:

Q8 0 is answer a is correct

Q9  Given:- The given data is 30, 32, 45, 54, 74, 78, 108, 112, 66, 76, 88, 40, 14, 20, 15, 35, 44, 66, 75, 84, 95, 96, 102, 110, 88, 74, 112, 14, 34, 44.

To find:- The number of classes in the distribution.

Solution:-

Given data frequency is vary from 14 - 112.

A grouped frequency distribution table with classes of equal sizes using 63-72.

So,the classes are :-

1) 13-22

2) 23-32

3) 33-42

4) 43-52

5)53-62

6) 63-72

7) 73-82

8) 83-92

9) 93-102

10) 103-112

Hence,the number of classes in the distribution will be 10.(Ans)