Mean of Grouped Data

The arithmetic mean of $10$ observations is $12.45$. If each reading is increased by $5,$ then the resulting mean is increased by

With usual meanings of notations, formula for assumed mean method for A.M. is

Find the mean of $x+1, x+3, x+4, x+8$.

The mean weight of students of a particular class is $52\mathrm{kg}$. The mean weight of boys of this class is $56\mathrm{kg}$ and that of girls is $50\mathrm{kg}$. Find the ratio of number of boys to the number of girls in the class.

Mean of $35$ observation is $75$. The mean of first $18$ observation is $70$ and the mean of last $18$ observation is $80$ find the ${18}^{\text{th}}$ observation.

The average weight of pupils of a class is $46 kg$ . The average weights of boys and girls are respectively $50 kg$ and $40 kg$ . The ratio of the number of boys to the number of girls is

The mean of $25$ observation is $36$. If the mean of the first $13$ observation is $32$ and that of the last $13$ observation is $39$, then the $13th$ observation is

The mean of five consecutive number is $7$. Which is the highest number?    

The mean of first ten odd natural numbers is

The mean age of a combined group of men and women is $25$years. If mean age of men is $26$ and that of women is $21$, then the percentage of men and women in the group is 

A class is divided into two sections $A$ and $B$. Passing average of $20$ students of section $A$ is $80\%$ and passing average of $30$ students of section $B$ is $70\%$. What is the passing average of both of the students?

The average monthly income of four earning members of a family is Rs.$7350$. One member passes away and the average monthly income becomes Rs.$6500$. What was the monthly income of the person, who is no more?

The mean of $‘n’$ numbers of a series is $\overline{\mathrm{X}}$. If the sum of first $(n – 1)$ terms is $\text{'}k\text{'}$ then the $n^{th}$ number is

A person covers half of his journey at $30 \mathrm{km}/\mathrm{hr}$ and the remaining half at $20 \mathrm{km}/\mathrm{hr}$. The average speed for the whole journey is

The average of first five multiples of $3$ is

The average of three numbers is $20$. If two of the numbers are $16$ and $22$, then the third is

The mean of first eight prime numbers is

The mean of three numbers is $11$ more than the least of the given numbers and $15$ less than the greatest number among them. If the median of the three numbers is $10$, then their sum is

What will be value of standard deviation$\left(\sigma \right)$ of $2, 4, 6, 8, 10 \left[\sigma =\sqrt{\frac{\sum {\left(X-\overline{X}\right)}^2}{N}}\right]$.

 The mean of six numbers is $20$. If one number is excluded, the mean is $15$. Then the value of the excluded number is