Demand $($Units$)$

Frequency $($Weeks$)$

Prob

Cumulative Probability

Demand

$$

$$

$$

$0$

$110$

$110$

$16$

$0\mathrm{.}16$

$0\mathrm{.}16$

$120$

$120$

$23$

$0\mathrm{.}23$

$0\mathrm{.}39$

$130$

$130$

$31$

$0\mathrm{.}31$

$0\mathrm{.}70$

$140$

$140$

$30$

$0\mathrm{.}30$

$1\mathrm{.}00$

$$

Total

$100$

$$

$$

$$

$$

$$

$$

$$

What is the cumulative probability of demand being at least $120$ units?