stressedadfff
Well-Known Member
- Joined
- May 8, 2021
- Messages
- 1,404
- Gender
- Female
- HSC
- 2021
Students helping students, join us in improving Bored of Studies by donating and supporting future students!
P(X > 8) = P((X-6)/3 > 2/3)) = P(Z > 2/3)hey guys can anyone explain b i have the solution but dont understand why its -2/3 and not just 2/3
View attachment 32284
wouldnt it be 1-p(z<2/3) the complement?P(X > 8) = P((X-6)/3 > 2/3)) = P(Z > 2/3)
Note that we cannot say b = 2/3 because P(Z > b) is not equal to P(Z < b). Therefore, to get P(Z < b) we use the symmetry of the standard normal distribution which tells us that
P(Z > 2/3) = P(Z < -2/3)
Hence b = -2/3.
thank you!@stressedadfff:
Let the point whereis a tangent to
be at
.
From the diagram,is in quadrant 4 and so
and
.
Now, you know thatlies on the line, and so you have
You also know that the gradient of the curve atis
since that is the gradient of its tangent. Using calculus, you can find this gradient at
and you also know that
lies on the curve.
This should allow you to find that:
Whilst it is true thatwouldnt it be 1-p(z<2/3) the complement?