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**Exercise 15.1**

**Find the mean deviation about the mean for the data in Exercises 1 and 2.**

**1. 4, 7, 8, 9, 10, 12, 13, 17**

**Ans. **Mean of the given data

Mean deviation about mean = = = 3

**2. 38, 70, 48, 40, 42, 55, 63, 46, 54, 44**

**Ans. **Mean of the given data

Mean deviation about mean =

= = 8.4

**Find the mean deviation about the median for the data in Exercises 3 and 4.**

**3. 13, 17, 16, 14, 11, 13, 10, 16, 11, 18, 12, 17**

**Ans. **Arranging the data in ascending order, 10, 11, 12, 13, 13, 14, 16, 11, 18, 12, 17

Here, (even number)

Mean =

= = 13.5

Mean deviation about median =

= = 2.33

**4. 36, 72, 46, 42, 60, 45, 53, 46, 51, 49**

**Ans. **Arranging the data in ascending order, 36, 42, 45, 46, 46, 49, 51, 53, 60, 72

Here, (even number)

Mean = = = 47.5

Mean deviation about median =

= = 7

**Find the mean deviation about the mean for the data in Exercises 5 and 6.**

**5. **

**Ans. **

Mean

= = 14

Mean deviation about mean =

= = 6.32

**6. **

**Ans. **

Mean

= = 50

Mean deviation about mean =

= = 16

**Find the mean deviation about the median for the data in Exercises 7 and 8.**

**7. **

**Ans. **

Here, = 13 and = 7

Median = 7

Mean deviation about median =

= = 3.23

**8. **

**Ans. **

Here, = 14.5 and = 21

Median = 30

Mean deviation about median =

= = 5.1

**Find the mean deviation about the mean for the data in Exercises 9 and 10.**

**9. **

**Ans. **

Mean

= = 358

Mean deviation about mean =

= = 157.92

**10. **

**Ans. **

Mean

= = 125.3

Mean deviation about mean =

= = 11.28

**11. Find the mean deviation about median for the following data:**

**Ans. **

Here, = 25

Median class = 20 – 30

Median =

= 20 + 7.86 = 27.86

Mean deviation about median =

= = 10.37

**12. Calculate the mean deviation about median age for the age distribution of 100 persons given below:**

**Ans. **

Here, = 50

Median class = 35.5 – 40.5

Median =

= 35.5 + 2.5 = 38

Mean deviation about median =

= = 7.35

Bhut hi achi site ha smjh ma assani sa aagya

Error: for Q.5) mean deviation about mean=158/25=6.32 not 1258/25

Bilkul bekar sara short cut me likha hua hai puri shi se smja nhi rhe ho??

Thanks

Boht Achha a simple way se btaya hai

Samjane ka trika bda acha h bilkul hamare sir ki tarah ???