A company has carried out a personnel selection process. a) ( 1.25 points) It is known that $40 \%$ of the total number of applicants have been selected in the process. If among the applicants there was a group of 8 friends, calculate the probability that at least 2 of them have been selected. b) (1.25 points) The scores obtained by the applicants in the selection process follow a normal distribution, X, with mean 5.6 and standard deviation $\sigma$. Knowing that the probability of obtaining a score $\mathrm { X } \leq 8.2$ is 0.67, calculate $\sigma$.
A company has carried out a personnel selection process.
a) ( 1.25 points) It is known that $40 \%$ of the total number of applicants have been selected in the process. If among the applicants there was a group of 8 friends, calculate the probability that at least 2 of them have been selected.
b) (1.25 points) The scores obtained by the applicants in the selection process follow a normal distribution, X, with mean 5.6 and standard deviation $\sigma$. Knowing that the probability of obtaining a score $\mathrm { X } \leq 8.2$ is 0.67, calculate $\sigma$.