Suppose that X is the number of bears spotted by tourists to Banff, Canada. The table below is the probability distribution for X. What is the expected value of X, that is, what is the mean of its distribution?

X 0 1 2 3 4

Probability 0.2 0.1 0.4 0.15 0.15

Expected value of X = 1.95

Step-by-step explanation:

Expected value of X, E(X) = ∑XP(X)

∑ = Summation

X = number of bears spotted

P(X) = probability of a certain number of bears spotted

E(X) = (0*P(X=0)) + (1*P(X=1)) + (2*P(X=2)) + (3*P(X=3)) + (4*P(X=4))

E(X) = (0*0.2) + (1*0.1) + (2*0.4) + (3*0.15) + (4*0.15)

E(X) = 0 + 0.1 + 0.8 + 0.45 + 0.60 = 1.95

x = -2

y = 848

step-by-step explanation:

plug in the numbers

step-by-step explanation:

the original amount doesn't ''re just looking for the time it takes for 1/2 of the substance to we have

(1/2) =)     take the ln   of both sides

ln (1/2)   = )   and we can write

ln(1/2) = ) lne     and lne   = 1     so we have

ln(1/2) = -.1092t     divide both sides by -.1092

t = ln(1/2)/-.1092 = about 6.347 days = about 6.3 days (rounded)