Question

find the sum of the lower limit of the median class and the upper limit of the modal class
CLASS 10-20,20-30,30-40,40-50,50-60,60-70.
FREQUENCY 1,3,5,9,7,3​

Answer 1

Answer:

90. is the sum of the Modal class

Answer 2

Answer:

90 is the required value .

Step-by-step explanation:

Explanation:

Given , class : 10-20,20-30,30-40,40-50,50-60,60-70

          frequency : 1,3,5,9,7,3

Step1:

Now find the Cumulative frequency

Where cumulative frequency can be calculated by adding the frequency of the first class interval to the frequencyof the second class interval .

After that ,the sun is added to the frequency of the third class interval  and so on.

Cumulative frequency :

1 , 1+3=4, 4+5 =9,9+9 =18 , 18+7 =25 , 25+3=28.

As we know ,

Median = $\frac{N}{2}th$ = $\frac{28}{2} = 14$th term        (Where N = ∑fi)

Cumulative frequency just greater than $\frac{N}{2}$ =14 is 18

∴  median class = 40-50

So the lower limit of the median class = 40

Step 2:

Modal class is the class interval with the heighest frequency in the frequency table .

Therefore we have ,maximum frequency = 9

So , modal class = 40-50

then the upper limit = 50

Step 3:

Now,

The sum of lower limit of the median class + the upper limit of the modal class

= 40+50 = 90 .

Final answer :

Hence , 90 is the sum of lower limit of the median class and the upper limit of the modal class.