# Thread: Probability Help Questions!!!!!!! URGENT!

1. ## Probability Help Questions!!!!!!! URGENT!

Heya,

Could you please explain to me how you would do these. You might need a calculator.

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The probability that Travis scores a goal in basketball fromthe 3 metres line is 0.65. In the last 4 mintues of practice, he shoots for a basket 8 times.

The chance he scores 5 goals is:

The probability he scores atleast 2 goals is:

The probability that he scores goals only with the first 6 shots are:

2. Originally Posted by mibamars
Heya,

Could you please explain to me how you would do these. You might need a calculator.

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The probability that Travis scores a goal in basketball fromthe 3 metres line is 0.65. In the last 4 mintues of practice, he shoots for a basket 8 times.

The chance he scores 5 goals is:

The probability he scores atleast 2 goals is:
these two questions are just using the binomial distribution. (do you remember the formula?)

we have $\displaystyle P(\mbox{k goals in 8 tries}) = P(X = k) = {8 \choose k}(0.65)^k(0.35)^{8 - k}$

for the first question, you want $\displaystyle P(5)$

for the second, you want $\displaystyle P(X \ge 2) = P(2) + P(3) + \dots P(8) = 1 - P(0) - P(1)$

The probability that he scores goals only with the first 6 shots are:
this means he scores the first 6 times and then misses the last two times.

the probability is: $\displaystyle (0.65)^6(0.35)^2$

3. I dont think you are right.

1) 0.279

2) 0.996

3) 0.009

I would just like to know how they got them.

4. Originally Posted by mibamars
I dont think you are right.

what are you not sure about? do you know what $\displaystyle {8 \choose k}$ means, for instance? i mean $\displaystyle _8C_k$, as in the combination