139 14 clASSMAte Date Page Calculate the median from the following frequency distribution! Class frequency cf
5-10. 5. 5
10-15. 6. 11
15-20. 15 26
20-25. 10. 36
25-30. 5. 41
30-35. 4. 45
35-40. 2. 47
40-45. 2. 49​

Answer :

Answer:

To find the median from the given frequency distribution, follow these steps:

1. **Identify the Median Class**:

- The median is the value that separates the higher half from the lower half of the data set.

- First, find the total number of observations (N). This is the cumulative frequency (cf) of the last class.

- Here, \( N = 49 \).

2. **Locate the Median Position**:

- The median position can be found using the formula \( \frac{N}{2} \).

- So, the median position is \( \frac{49}{2} = 24.5 \).

3. **Determine the Median Class**:

- The median class is the class interval where the cumulative frequency just exceeds or contains the median position (24.5).

- From the cumulative frequencies given, the median class is 15-20, as its cumulative frequency is 26, which contains 24.5.

4. **Apply the Median Formula**:

- Use the formula for the median in a grouped frequency distribution:

\[

\text{Median} = L + \left(\frac{\frac{N}{2} - CF}{f}\right) \times h

\]

- Here:

- \( L \) is the lower boundary of the median class.

- \( CF \) is the cumulative frequency of the class before the median class.

- \( f \) is the frequency of the median class.

- \( h \) is the class width.

For the given data:

- \( L = 15 \) (lower boundary of the median class 15-20)

- \( CF = 11 \) (cumulative frequency of the class before the median class 10-15)

- \( f = 15 \) (frequency of the median class 15-20)

- \( h = 5 \) (class width)

Substitute these values into the formula:

\[

\text{Median} = 15 + \left(\frac{24.5 - 11}{15}\right) \times 5

\]

Simplify the expression inside the parentheses:

\[

\text{Median} = 15 + \left(\frac{13.5}{15}\right) \times 5

\]

\[

\text{Median} = 15 + \left(0.9\right) \times 5

\]

\[

\text{Median} = 15 + 4.5 = 19.5

\]

Thus, the median of the frequency distribution is **19.5**.

This method effectively provides the median for grouped data by identifying the median class and applying the appropriate formula [[❞]](https://quizgecko.com/learn/survey-of-india-map-sheet-g43s10-analytical-questions-effnfc).

Answer:

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Explanation:

Σfi= 49

N = Σfi = 49

⇒ N/2 = 24.5

The cumulative frequency greater than 24.5 is 26 and the corresponding class is 15-20.

Thus the median class is 15-20.

Therefore,

l= 15,

h = 5,

f= 15,

c.f. of preceding class = 11 and N/2 = 24.5

Median,

M = l + ((N/2 − cf)/f) × h

Median = 15 + ((24.5 – 11)/15) × 5

Median = 15 + 4.5

Median = 19.5

Hence, median is 19.5 .

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