*MEDAL*
For a standard normal distribution, which of the following expressions must always be equal to 1?
P(z≤-a)-P(-a≤z≤a)+P(z≥a)
P(z≤-a)-P(-a≤z≤a)+P(z≥a)
P(z≤-a)+P(-a≤z≤a)-P(z≥a)
P(z≤-a)+P(-a≤z≤a)+P(Z≥a)

Question

*MEDAL* 
For a standard normal distribution, which of the following expressions must always be equal to 1?
P(z≤-a)-P(-a≤z≤a)+P(z≥a)
P(z≤-a)-P(-a≤z≤a)+P(z≥a)
P(z≤-a)+P(-a≤z≤a)-P(z≥a)
P(z≤-a)+P(-a≤z≤a)+P(Z≥a)

amistre64 · Answer

the sum of all the probabilites underneath the curve