The batting average $\text{(BA)}$ of a test batsman is computed from runs scored and innings played-completed innings and incomplete innings (not out) in the following manner:
- $r_1$ = number of runs scored in completed innings;
- $n_1$ = number of completed innings
- $r_2$ = number of runs scored in incomplete innings;
- $n_2$ = number of incomplete innings
- $\text{BA} =\frac{r_1 + r_2}{n_1}$
To better assess batsman's accomplishments, the ICC is considering two other measures $\text{MBA}_1$ and $\text{MBA}_2$ defined as follows:
- $\text{MBA}_1 = \frac{r_1}{n_1} + \frac{n_2}{n_1} \: \: \max\left[0, \left(\frac{r_2}{n_2} - \frac{r_1}{n_1}\right)\right]$
- $\text{MBA}_2 = \frac{r_1 + r_2}{n_1 + n_2}$
An experienced cricketer with no incomplete innings has a $\text{BA}$ of $50.$ The next time he bats, the innings is incomplete and he scores $45$ runs. It can be inferred that:
- $\text{BA}$ and $\text{MBA}_1$ will both increase
- $\text{BA}$ will increase and $\text{MBA}_2$ will decrease
- $\text{BA}$ will increase and not enough data is available to assess change in $\text{MBA}_1$ and $\text{MBA}_2$
- None of these