Answer:
The approximate percentage of SAT scores that are less than 865 is 16%.
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
Approximately 68% of the measures are within 1 standard deviation of the mean.
Approximately 95% of the measures are within 2 standard deviations of the mean.
Approximately 99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean of 1060, standard deviation of 195.
Empirical Rule to estimate the approximate percentage of SAT scores that are less than 865.
865 = 1060 - 195
So 865 is one standard deviation below the mean.
Approximately 68% of the measures are within 1 standard deviation of the mean, so approximately 100 - 68 = 32% are more than 1 standard deviation from the mean. The normal distribution is symmetric, which means that approximately 32/2 = 16% are more than 1 standard deviation below the mean and approximately 16% are more than 1 standard deviation above the mean. So
The approximate percentage of SAT scores that are less than 865 is 16%.
Answer:
C
Step-by-step explanation:
x² - 6x + 13 = 0
x² - 2(x)(3) + 3² - 3² + 13 = 0
(x - 3)² = -4
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Answer:
![P(disease/positivetest) = 0.36116](https://tex.z-dn.net/?f=P%28disease%2Fpositivetest%29%20%3D%200.36116)
Step-by-step explanation:
This is a conditional probability exercise.
Let's name the events :
I : ''A person is infected''
NI : ''A person is not infected''
PT : ''The test is positive''
NT : ''The test is negative''
The conditional probability equation is :
Given two events A and B :
P(A/B) = P(A ∩ B) / P(B)
![P(B) >0](https://tex.z-dn.net/?f=P%28B%29%20%3E0)
P(A/B) is the probability of the event A given that the event B happened
P(A ∩ B) is the probability of the event (A ∩ B)
(A ∩ B) is the event where A and B happened at the same time
In the exercise :
![P(I)=0.025](https://tex.z-dn.net/?f=P%28I%29%3D0.025)
![P(NI)= 1-P(I)=1-0.025=0.975\\P(NI)=0.975](https://tex.z-dn.net/?f=P%28NI%29%3D%201-P%28I%29%3D1-0.025%3D0.975%5C%5CP%28NI%29%3D0.975)
![P(PT/I)=0.904\\P(PT/NI)=0.041](https://tex.z-dn.net/?f=P%28PT%2FI%29%3D0.904%5C%5CP%28PT%2FNI%29%3D0.041)
We are looking for P(I/PT) :
P(I/PT)=P(I∩ PT)/ P(PT)
![P(PT/I)=0.904](https://tex.z-dn.net/?f=P%28PT%2FI%29%3D0.904)
P(PT/I)=P(PT∩ I)/P(I)
0.904=P(PT∩ I)/0.025
P(PT∩ I)=0.904 x 0.025
P(PT∩ I) = 0.0226
P(PT/NI)=0.041
P(PT/NI)=P(PT∩ NI)/P(NI)
0.041=P(PT∩ NI)/0.975
P(PT∩ NI) = 0.041 x 0.975
P(PT∩ NI) = 0.039975
P(PT) = P(PT∩ I)+P(PT∩ NI)
P(PT)= 0.0226 + 0.039975
P(PT) = 0.062575
P(I/PT) = P(PT∩I)/P(PT)
![P(I/PT)=\frac{0.0226}{0.062575} \\P(I/PT)=0.36116](https://tex.z-dn.net/?f=P%28I%2FPT%29%3D%5Cfrac%7B0.0226%7D%7B0.062575%7D%20%5C%5CP%28I%2FPT%29%3D0.36116)
Answer:
c = -6
d = 2
Step-by-step explanation:
After reflection about the x-axis:
A --> A'
(2,3) --> (2,-3)
(4,3) --> (4,-3)
(2,6) --> (2,-6)
After translation:
(2 + c, -6 + d) --> (-4, -4)
2+c = -4
c = -6
-6+d = -4
d = 2