Question Bank

The mean of 100 observations was calculated as 40. Later it was found that an observation 53 was misread as 83. The corrected mean is:

If for a given data, $\sum (x-5) = 10$ and $n=20$, then the mean is:

For a data set with 50 items, the mean is 100. If each of the first 25 items is increased by 2, and each of the last 25 items is decreased by 2, the new mean is:

If the mean of $n$ numbers is $M$, and the sum of first $(n-1)$ numbers is $S$, the $n^{th}$ number is:

Calculate the mode for the following data: 2, 3, 3, 5, 5, 5, 7, 7, 8, 8, 8. What can be said?

The combined mean of two groups of 40 and 60 observations are 25 and 30 respectively. The combined mean is:

If the mean of first $n$ natural numbers is $3n/5$, then $n$ is:

In a continuous series, the median is 35 and the median class is 30-40. If f=10 and h=10, and N=50, what is the 'cf' of the pre-median class?

If the ratio of mode and median of a distribution is 6:5, then the ratio of mean and median is:

The mean of 20 observations is 15. On checking, it was found that two observations 20 and 15 were miscopied as 3 and 32. The correct mean is:

Find the median of the following frequency distribution: x=5, 10, 15, 20 with f=3, 7, 6, 4.

If the mean of $a, b, c, d, e$ is 28, and the mean of $a, c, e$ is 24, what is the mean of $b, d$?

Which of the following cannot be determined graphically?

In a moderately skewed distribution, the values of Mean and Median are 12 and 13 respectively. The value of Mode is:

If the mean of $x$ and $1/x$ is $M$, then the mean of $x^2$ and $1/x^2$ is:

The average weight of 8 persons is increased by 2.5 kg when a new person comes in place of one of them weighing 65 kg. The weight of the new person is:

If the mean of observations $x_1, x_2, ... x_n$ is $\bar{x}$, then $\sum_{i=1}^n (x_i - \bar{x})$ is:

Find the median of the series: 3, 3.5, 2.5, 4.5, 5, 2, 0.5, 6, 7.

In a distribution of 100 observations, the sum of observations is 500. If the sum of squares of observations is 3000, the mean is:

If the mean of first $n$ odd natural numbers is $n^2/81$, find $n$.