Find cumulative distribution

[m.ooo]

Okay so I have this exam prep but I dont really understand how I am supposed to solve this. Can anyone help?

 

[BigBeachBanana]

Okay so I have this exam prep but I dont really understand how I am supposed to solve this. Can anyone help?View attachment 32015

First figure out what's p(10) is. Hint: the sum of pmf must equal 1.
Next, compose the F(x).

 

[m.ooo]

First figure out what's p(10) is. Hint: the sum of pmf must equal 1.
Next, compose the F(x).

Seriously, I don't know why I stuck on that question for so long. Thanks!
*The answer is 4/5

 

[pka]

Seriously, I don't know why I stuck on that question for so long. Thanks!
*The answer is 4/5

No the answer is $\dfrac{4}{10}$ they must add to $1$

 

[m.ooo]

No the answer is $\dfrac{4}{10}$ they must add to $1$

The F(17) is 8/10 -> 4/5. I assume you're talking about the p(10).

 

[m.ooo]

$$F(a) = \begin{cases} 0 &\text{if } a<0 \\ 1/10 &\text{if } 0\le a <5 \\ 5/10 &\text{if } 5\le a <10 \\ 8/10 &\text{if } 10\le a <15 \\ 1 &\text{if } a\ge15 \\ \end{cases}$$I don't see how the answer can be 4/5.

Well, my bad, I had in mind that F(a)=8/10 if 15<=a<20 .

 

[BigBeachBanana]

$$F(a) = \begin{cases} 0 &\text{if } a<0 \\ 1/10 &\text{if } 0\le a <5 \\ 5/10 &\text{if } 5\le a <10 \\ 8/10 &\text{if } 10\le a <15 \\ 1 &\text{if } a\ge15 \\ \end{cases}$$I don't see how the answer can be 4/5.

Correction:
$$F(a) = \begin{cases} 0 &\text{if } a<5 \\ 1/10 &\text{if } 5\le a <10 \\ 5/10 &\text{if } 10\le a <15 \\ 8/10 &\text{if } 15\le a <20 \\ 1 &\text{if } a\ge20 \\ \end{cases}$$Therefore, $F(17)=8/10=4/5$

 

[pka]

The F(17) is 8/10 -> 4/5. I assume you're talking about the p(10).
My bad. Yes that was $p(10)$. So $F(17)=\dfrac{8}{10}$