Comparison of Discrete and Continuous Probability Functions
Discrete
Continuous
Can talk about
P
(
x
=
a
)
P
(
x
=
a
)
≈
0
probability distribution function
probability density function
f
(
a
)
=
P
(
x
=
a
)
∫
a
b
f
(
t
)
dt
=
P
(
a
≤
x
≤
b
)
f
(
a
)
≥
0
for all
a
f
(
a
)
≥
0
for all
a
∑
f
(
a
)
=
1
∫
-
∞
∞
f
(
t
)
dt
=
1
pdf version