What are the mean and standard deviation of the random variable X?

Okay so this is a binomial distrubution as binomial is yes or no

so whether the number of males in the sample who have this chromosome defect is yes or no.They either have it or not.

Binomial is represented by X~Bin( n , p)

Where n = the number in the sample group , in this case 100

and p= proportion , so proportion of males who have the chromosome defect which is ( 1/200) =0.005

To find the mean using binomial distrubtion it can be found by multiplying n with p

so in this case 100x0.005 , thus mean = 0.5

While variation is found by -------->np(1-p)

so in this case -------------> 100x0.005(1-0.005)=0.5x0.995

=0.4975

to find your standard deviation u simply square root the variance

so standard deviation = 0..4975^0.5

standard deviation =0.70533

Hope that helps