Question

extra questions for statistics chapter for class 10
​

Answer 1

Answer:

Q.1. Find the mean of the 32 numbers, such that if the mean of 10 of them is 15 and the mean of 20 of them is 11. The last two numbers are 10.

Solution: The given mean of 10 numbers = 15

So, Mean of 10 numbers = sum of observations/ no. of observations

15 = sum of observations / 10

Sum of observations of 10 numbers = 150

Similarly, Mean of 20 numbers = sum of observations/ no. of observations

11 = sum of observations / 20

Sum of observations of 20 numbers = 220

Hence, Mean of 32 numbers = (sum 10 numbers+sum of 20 numbers +sum of last two numbers)/ no. of observations

Mean of 32 numbers = (150 +220 + 20 ) / 32 = 390 /32 = 12.188

Q.2. Find the mean of the first 10 natural numbers.

Solution: The first 10 natural numbers are 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

Mean = (1 +2 +3 +4 +5+ 6+ 7+ 8+ 9+10) / 10 = 55/10 =5.5

Q.3. Find the value of y from the following observations if these are already arranged in ascending order. The Median is 63.

20, 24, 42, y , y +2, 73, 75, 80, 99

Solution:

As the number of observations made is odd, so the median will be the middle term, i.e. y+2. Therefore,

y + 2 = 63

y = 63 -2 = 61

Q.4 While checking the value of 20 observations, it was noted that 125 was wrongly noted as 25 while calculating the mean and then the mean was 60. Find the correct mean.

Solution:

Let y be the sum of observation of 19 (20 – 1) numbers leaving 125,

So, y + 25 = 20 × 60 = 1200 (Mean = sum of observations/ no. of observations)

As we know,

x+25=20×60=1200

Also

x+125=20×y=20y

Next, Subtract 125−25=20y−1200

20y=1300

y=65

Q.5. Find the mode of the following items.

0, 5, 5, 1, 6, 4, 3, 0, 2, 5, 5, 6

Solution: On arranging the items in ascending order, we get:

0, 0, 1, 2, 3, 4, 5, 5, 5, 5, 6, 6

As we can see 5 occurs the maximum number of times.

So, the mode is = 5

Q.6. A student scored the following marks in 6 subjects:

30, 19, 25, 30, 27, 30

Find his modal score.

Solution: If we arrange his marks in ascending order

19, 25, 27, 30, 30, 30

As we can see, 30 occurs a maximum number of times. So, The mode is 30.

Step-by-step explanation:

HOPE IT HELPS UH!

MARK AS BRAINLIEST!