Statistics and Probability: JEE Main 2023 Mathematics question

If the variance of the frequency distribution $x_i$ | 2 | 3 | 4 | 5 | 6 | 7 | 8 Frequency $f_i$ | 3 | 6 | 16 | $\alpha$ | 9 | 5 | 6 is 3, then $\alpha$ is equal to _____________.