Statistics

The mean of a certain number of observations is $35$. What is the new value of the mean if each observation is increased by $20\%$.

The mean of $8$ observations was found to be $20$. Later it was detected that one of the observations was misread as $62$. What is the correct observation, if the correct mean is $15.5$?

The mean of $25$ observations is $32$. It was later discovered that $38$ and $29$ are misread as $25$ and $42$. Find the correct mean.

The class mean score on a test was $60$, and the standard deviation was $15$. lf Elena's score was within $2$ standard deviations of the mean, what is the lowest score she could have received?

The mean of first $8$ observations is $18$ and last $8$ observations is $20$. If the mean of all $15$ observations is $19$, find the $8^{th}$ observation

If $\bar{x_1} , \bar{x_2} , \bar{x_3} , ... , \bar{x_n}$ are the means of n groups with $n_1, n_2, ... , n_n$ number of observations respectively, then the mean x of all the groups taken together is given by :

If $\sum_{i=1}^{9}{(x_{i}-99)}=27$ and $\sum_{i=1}^{9}{(x_{i}-99)^{2}}=306$ then the mean of the squares of the deviation of $x_{1}, x_{2},..........., x_9$ from their $AM$ is

If marks scored by students of a class are 1, 2, 4,......,${ 2 }^{ 10 }$ with frequencies 1, 2, 3, 4,......,11, then median is _________.

Ten observation 6, 14, 15, 17, x+1, 2x-13, 30, 32, 34, 43 are written is ascending order. The media of the data is 24. The mean of the data is _________.

When 10 is subtracted from all the observations, the mean is reduced to 60% of its value. If 5 is added to all the observations, then the mean will be

Which of the following does not change for the observation $23, 50, 27, 2x, 48, 59, 72, 89, 5x, 100, 120$ when $x$ lies between $15$ and $20$?