Answer:
The probability is 0.9211
Step-by-step explanation:
Let's call K the event that the student know the answer, G the event that the student guess the answer and C the event that the answer is correct.
So, the probability P(K/C) that a student knows the answer to a question, given that she answered it correctly is:
P(K/C)=P(K∩C)/P(C)
Where P(C) = P(K∩C) + P(G∩C)
Then, the probability P(K∩C) that the student know the answer and it is correct is:
P(K∩C) = 0.7
On the other hand, the probability P(G∩C) that the student guess the answer and it is correct is:
P(G∩C) = 0.3*0.2 = 0.06
Because, 0.3 is the probability that the student guess the answer and 0.2 is the probability that the answer is correct given that the student guess the answer.
Therefore, The probability P(C) that the answer is correct is:
P(C) = 0.7 + 0.06 = 0.76
Finally, P(K/C) is:
P(K/C) = 0.7/0.76 = 0.9211
11. 9/20
12. 13/20
13. 12/20
that's if it doesn't have to be in percentage form
Answer:
Confidence Interval - 2.290 < S < 2.965
Step-by-step explanation:
Complete question
A chocolate chip cookie manufacturing company recorded the number of chocolate chips in a sample of 50 cookies. The mean is 23.33 and the standard deviation is 2.6. Construct a 80% confidence interval estimate of the standard deviation of the numbers of chocolate chips in all such cookies.
Solution
Given
n=50
x=23.33
s=2.6
Alpha = 1-0.80 = 0.20
X^2(a/2,n-1) = X^2(0.10, 49) = 63.17
sqrt(63.17) = 7.948
X^2(1 - a/2,n-1) = X^2(0.90, 49) = 37.69
sqrt(37.69) = 6.139
s*sqrt(n-1) = 18.2

confidence interval:
(18.2/7.948) < S < (18.2/6.139)
2.290 < S < 2.965
It's a linear function. We need only two points to sketch the graph.
f(x) = -5x + 4 → y = -5x + 4
for x = 0 → y = -5(0) + 4 = 0 + 4 = 4 → (0, 4)
for x = 1 → y= -5(1) + 4 = -5 + 4 = -1 → (1, -1)
The domain and the range is the set of all real numbers.