Difference calculation formula

Do it.

Eξ=0×(? -p)+ 1×p+2×？

= 1+p

Dξ=0×(? -p)^2+ 1×p^2+2×(？ )^2=? +p^2

Further, remember the definitions of expectation and variance, which is the origin of the calculation formula. More importantly, we should understand the meaning of expectation and variance. Expectation means average, and variance means the degree of deviation from the average.