Mean

Q.

The mean of five numbers is $27$.If one number is excluded their mean is $25$. find the excluded number.

Q. The ___ of a number of observations is the sum of the values of all the observations divided by the total number of observations.

Q. The median of the distribution $2,3,4,7,5,1,6$ is:

1. $3$
2. $1$
3. $4$
4. $2$

Q. The mean of 6 numbers is 24. If one number excludede, the mean of remaining numbers becomes 22. Find the excluded number.

Q. The height of 5 students (in cm) are as below.
{140, 145, 130, 135, 150}
Their mean value is equal to

1. 120 cm
2. 130 cm
3. 140 cm
4. 150 cm

Q. Mean is a measure of ___ (median/central) tendency.

Q. An object covers half its journey with a speed of 40m/s and the other half with a speed of 60m/s. Find its average speed for the whole journey.

Q. Choose the right answers from the options given for each of the following questions.
If the average of the numbers 33, 34, 35, x , 37, 38, 39 is 36, what is the value of x ?
(i) 40
(ii) 32
(iii) 42
(iv) 36

Q.

Using the assumed - mean method, find the mean height of the plants from the following frequency-distribution table:

$\begin{array}{cccccc}{\text{Height (in cm) x}}_i& 60& 64& 68& 72& 76\\ {\text{Number of plants f}}_i& 5& 16& 40& 30& 9\end{array}$
[4 MARKS]

Q.

Find the mean of the first six multiples of $5$.

Q. The median of a given data set or observations is the middle-most value after arranging the data in an ascending or a descending order.

1. True
2. False

Q.

The mean of 15 observations is 8. If the mean of the first eight observations is 7 and that of the last eight observations is 10, then the value of the 8th observation is 16.

1. 16

2. 12

Q.

Find the value of 'p' if the mean of the following data is 17.

$$\begin{array}{cccccc}{x}_i& 10& p& 18& 21& 25\\ f_i& 10& 15& 7& 9& 9\end{array}$$

1. 12

2. 14

3. 18

4. 16

Q.

Question 82(iii)
In a public library, the following observations were recorded by the librarian in a particular week.
$\begin{array}{ccccccc}& & & & & & \\ \text{Days}& \text{Mon}& \text{Tue}& \text{Wed}& \text{Thur}& \text{Fri}& \text{Sat}\\ \text{Newspaper readers}& 400& 600& 350& 550& 500& 350\\ \text{Magazine readers}& 150& 100& 200& 300& 250& 200\end{array}$
What is the mean number of magazine readers?

Q.

Find the sum of $8$ numbers whose mean is $13$.

Q. The median of the distribution $2,3,4,7,5,1,6$ is:

1. $2$
2. $3$
3. $4$
4. $1$

Q. If the mean of five observations $x,x+2,x+4,x+6andx+8$ is $11$, then the mean of first three observations is:

1. 6
2. 4
3. 9
4. 8

Q. is a measure of central tendency

1. Frequency
2. Class interval
3. Mean
4. Class

Q.

You have to buy a pair of running shoes. You have 3 brands: Ruma, Peebok and Abibas. You go online and search for reviews of different brands. There you saw that on the basis of stars, brands are rated. More stars imply better rating. Which brand has the highest average rating?

​

1. Ruma

2. Peebok

3. Abibas

4. Both Abibas and Ruma have the same rating.

Q. The weighted mean of first n natural numbers whose weights are equal to the corresponding number is equal to

1. $\frac{1}{3}(2n+1)$
2. $\frac{1}{2}(n+4)$
3. $\frac{1}{5}(2n+3)$
4. None of these

Q.

The mean of the following distribution is: 16.5

$$\begin{array}{ccccc}{x}_i& 15& 12& 18& 19\\ f_i& 2& 5& 7& 6\end{array}$$

1. 15.2

2. 15.35

Q.

Find the mean of the given data - 5 , 4 , 7 , 9 , 10 is 7.

1. False

2. True

Q.

Virender Sehwag’s score card for a five match ODI series is 23, 89, 76, 54, 102 runs respectively. What is Sehwag’s mean score for the tournament?

1. 66.8

2. 67.8

3. 68.8

4. 65.8

Q.

The following are the number of books issued in a school library during a week: $105,216,322,167,273,405$ and $346$. Find the average number of books issued per day.

Q.

The test results of a class were tabulated. Who was the student whose score lies exactly in the middle of all the students in that class?

$\begin{array}{ccccccccc}RollNo& Name& Marks& RollNo.& Name& Marks& RollNo.& Name& marks\\ 1& Pavani& 96& 6& Goutham& 21& 11& Akash& 83\\ 2& Mahibur& 32& 7& Preeti& 85& 12& Sathyam& 78\\ 3& Deepthi& 93& 8& Kushagra& 45& 13& Aju& 98\\ 4& Karan& 81& 9& Pavan& 90& 14& Akshit& 65\\ 5& Sarosh& 61& 10& Vignesh& 54& 15& Ajit& 73\end{array}$

1. Karan
2. Sathyam
3. Vignesh
4. Ajit

Q.

Calculate the mean, median and mode for the following data: 23, 17, 14, 17, 21, 14,

Q. The maximum temperature of a city during $7$th June $2021$ to $13$th June $2021$ is as follows:

The average temperature for the given week is

1. ${22.9}^{\circ }$

2. ${24}^{\circ }$
3. ${23.2}^{\circ }$
4. ${23}^{\circ }$
5. ${25}^{\circ }$
6. ${24.5}^{\circ }$

Q. If the mean of the following distribution is 2.6 then the value of y is
$\begin{array}{cccccc}Variable\left(x\right)& 1& 2& 3& 4& 5\\ Frequency& 4& 5& y& 1& 2\end{array}$

1. 3
2. 8
3. 13
4. 24

Q.

The mean of 100 observations is 50. If in one of the observations 50 is replaced by 150, the resulting mean will be

1. 52

2. 51

3. 50.5

4. 51.5

Q.

Find the mean of first five multiples of 5. [2 MARKS]