IX M SAII STATISTICS TEST

Q 1.     (2)The class marks of a distribution are 105, 115, 125, 135, 145. Find class size and class limits.                                                                                                                                                       

Q 2.    (2) The following observations have been arranged in ascending order. If the median of the data is 63, find the value of x.                 

         29, 32, 48, 50, x, x + 2, 72, 78, 84, 95                                                                                           

Q 3.   Find  mean & mode of the following data:                                                                                                

Marks	10	20	30	40	50	60	70
Number of students	7	9	10	18	22	16	8

Q 4.     (3)If mean of observations  is 9, find mean of last 3 observations.                  

Q 5.    (3)The mean of a data is 64. Find the new mean if  each of the observation of a data is

  (a) increased by 2   (b) decreased by 3         (c) multiplied by 0.25                                                   

Q 6.    (4)  Draw a histogram for marks of students given below:                                                                             

Marks                        0 – 10           10 – 30               30 – 45              45 – 50        50 – 60

No of students            8                      32                     18                        10              6                            

Q 7.    (4)Construct a frequency polygon for following data without using histogram:                                 

Income (in Rs)                            No. of workers

  60 – 90                                          12

 90 – 120                                         14

120 – 150                                        18

150 – 180                                        10

180 – 210                                        9

210 – 240                                       4                                                                                    

Q 8. (4)If mean of the following data is 20.6 and and total observation is 50 , find missing frequencies:                       

                      x               10        15        20        25        35

                     f                 3          f₁        25         f₂          5                                                                                               

Q 9.     (4) The marks obtained by 40 students of class IX are

18, 8, 12, 6, 8, 16, 12, 5, 23, 2, 10, 20, 12, 9, 7, 6, 5, 3, 5, 13, 21, 13, 15, 20, 24, 1, 7, 21, 16, 13, 18, 23, 7, 3, 18, 17, 16, 16, 23, 2.                                                                                                               

(i)                 Construct a frequency distribution table with one class being 15 – 20.

(ii)               Also construct a cumulative frequency distribution of more than type.                                                                                                                                                                                 )

IX SAII MATHS STATISTICS ASSIGNMENT

1.       The relative humidity (in %) of a certain city for a month of 30 days was as follows:

98.1	98.6	99.2	90.3	86.5	95.3	92.9	96.3	94.2	95.1
89.2	92.3	97.1	93.5	92.7	95.1	97.2	93.3	95.2	97.3
96.2	92.1	84.9	90.2	95.7	98.3	97.3	96.1	92.1	89

                (i) Construct a grouped frequency distribution table with classes 84 - 86, 86 - 88, etc.

                (ii) Which month or season do you think this data is about?

                (iii) What is the range of this data?

2.       100 surnames were randomly picked up from a local telephone directory and a frequency             distribution of the number of letters in the English alphabet in the surnames was found as follows:

Number of letters	1 - 4	4 - 6	6 - 8	8 - 12	12 - 20
Number of surnames	6	30	44	16	4

                (i) Draw a histogram to depict the given information.

                (ii) Write the class interval in which the maximum number of surnames lie.

3.       The length of 40 leaves of a plant are measured correct to one millimetre, and the obtained data is represented in the following table:                      

Length (in mm)	118 - 126	127 - 135	136 - 144	145 - 153	154 - 162	163 - 171	172 - 180
Number of leaves	3	5	9	12	5	4	2

                (i) Draw a histogram to represent the given data.

                (ii)Also represent by a polygon ( Separately )

                (iii) Is it correct to conclude that the maximum number of leaves are 153 mm long? Why?

4.       Find out mean, mode  ( Calculate).

Marks	10	20	30	40	50	60	70
Number of students	7	10	10	17	23	15	8

5.       Find the value of p if mean is 7.5

Marks	3	5	7	9	11	13
Number of students	6	8	15	p	8	4

6.       Find the value of  ‘m’ and ‘n’  if mean is 50 and total observations are 90.

Class Marks	10	30	50	70	90
Number of students	17	m	32	n	19

7.       Find median of 

20,26,8,18,24,18,46,23,62,55,70,44

8.       The class mark for a certain continuous frequency distribution are . find class intervals and draw hisrogram.

Class Marks	6	12	18	24	30
Number of students	12	15	20	9	16

9.       The mean of a data is 46. Find the new mean if  each of the observation of a data is

(a) increased by 3   (b) decreased by 2         (c) multiplied by 0.5

10.   Find less than and more than cumulative frequency.

Number of letters	0 - 4	4 - 8	8 - 12	12 - 16	16 - 20
Number of surnames	6	17	23	13	11