# The production of electric bulbs in different factories is shown in the following table. Find the median of the productions. No. of bulbs produced (Thousands) 30 - 40 40 - 50 50 - 60 60 - 70 70 - 80 - Algebra

Sum

The production of electric bulbs in different factories is shown in the following table. Find the median of the productions.

 No. of bulbs produced (Thousands) 30 - 40 40 - 50 50 - 60 60 - 70 70 - 80 80 - 90 90 - 100 No. of factories 12 35 20 15 8 7 8

#### Solution

 Class No. of bulbs produced (in thousands) Frequency(Number of factories)fi Cumulaive frequency(less than) 30 - 40 12 12 40 - 50 35 47→cf 50 - 60(Median Class) 20→f 67 60 - 70 15 82 70 - 80 8 90 80 - 90 7 97 90 - 100 8 105 Total N = 105

Here, total frequency = Σfi = N = 105

∴ "N"/2 = 105/2 = 52.5

Cumulative frequency which is just greater than (or equal) to 52.5 is 67.

∴ The median class is 50 – 60.

Now, L = 50, f = 20, cf = 47, h = 10.

∴ Media = "L" + (("N"/2 - "cf")/"f") × h

= 50 + ((52.5 - 47)/20) × 10

= 50 + ((5.5)/20) × 10

= 50 + 2.75

= 52.75 thousand lamps

= 52.75 × 1000

= 52750 lamps

Hence, the median of the productions is 52750 lamps.

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Chapter 6: Statistics - Practice Set 6.2 [Page 146]

#### APPEARS IN

Balbharati Maths 1 Algebra 10th Standard SSC Maharashtra State Board
Chapter 6 Statistics
Practice Set 6.2 | Q 4 | Page 146

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