Statistics

Find the mean of marks obtained by 20 students in a class test (out of 50). 25, 40, 15, 16, 28, 39, 41, 22, 28, 30, 36, 40, 30, 18, 22, 32, 48, 32, 38, 40.

The mean marks secured by $25$ student of a $ section\ A$ of $ X $ class is $47 $ that of $35$ students of $ section\ B$ is $51$ and that of $30$ students of $ section \ C$ is $ 53$ , the mean marks of all student of three section are

Find the mean of $8, 12, 16, 22,10$ and $4$, Find the resulting mean, if each of the observations, given above. be d ecreased by $40\%.$.Find the mean

If $150$ is the mean of $200$ observations and $100$ is the mean of some $300$ other observations, find the mean of the combination.

CLASS INTERVAL $0-7$ $7-14$ $14-21$ $21-28$ $28-35$ $35-42$ $42-49$ FREQUENCY $19$ $25$ $36$ $72$ $51$ $43$ $28$ The arithmetic mean for the following frequency distribution is

Mean of $31$ observation is $65$ .If mean of first $15$ observation is $64$ and that of last $15$ observation is $66$ ,then the sixteenth observation is

Mean of 199 observations is 40. If mean of first 100 observations is 42.5 and that of last 100 observations is 39.5 then the hundredth observation is

Mean weight of 21 students of a group is 40 kg. If the mean weight of first 10 students is 42 kg and that of last 10 students is 38 kg, then the weight of 11 the student is

Mean weight of 25 students of a class is 60 kg. If mean weight of first 13 students is 57 kg and that of last 13 students is 63 kg, then the weight of the 13th students is

On Thursday, $20$ of the $25$ students in a chemistry class took a test and their average (arithmetic mean) was $80$. On Friday, the other $5$ students took the test and their average (arithmetic mean) was $90.$ What was the average for the entire class?

The average of $6$ observations is $12$. A new seventh observation is included and the new average is decreased by $1$. The seventh observation is

The mean weight of a class of $34$ students is $6.5$kg. If the weight of the teacher is included, the mean rises by $500$g. Then the weight of the teacher is __________.