For a given frequency distribution,$\Sigma f_{i} x_{i} = 1790$ and $\Sigma f_{i} = 50$. Then,the mean $\bar{x} = $ ..........

In the formula $\bar{x} = a + \frac{\sum f_{i} d_{i}}{\sum f_{i}}$ for finding the mean of grouped data,$d_{i}$ are deviations from $a$ of:

For a given frequency distribution,assumed mean $A = 25$,$\Sigma f_{i} d_{i} = 120$ and $\Sigma f_{i} = 140$. Then,the mean $\bar{x} = \dots$

In the formula $\bar{x} = \frac{\Sigma f_{i} x_{i}}{\Sigma f_{i}}$,$x_{i}$ represents ..........

For some given data, if $M = 15.4$ and $\bar{x} = 14.5$, then $Z = \dots$

In the formula $\bar{x} = a + h \left( \frac{\Sigma f_{i} u_{i}}{\Sigma f_{i}} \right)$,for finding the mean of grouped frequency distribution,$u_{i}$ is equal to