MHB Standard deviation, Normal Distributions and Taking Random Samples

AI Thread Summary
To find the standard score (z-score) for the data value of 9 from a normal distribution with a mean of 16.8 and a standard deviation of 2.3, the formula used is z = (x - μ) / σ. Substituting the values, z = (9 - 16.8) / 2.3. This calculation results in a z-score of approximately -3.35. The discussion emphasizes the importance of showing progress when asking for help to facilitate better assistance. Understanding how to apply the z-score formula is crucial for analyzing data within normal distributions.
DarcyDorian
Messages
1
Reaction score
0
Find the standard score for a the data value 9 from a normal distribution which has a
mean of 16.8 and a standard deviation of 2.3
 
Mathematics news on Phys.org
Hello and welcome to MHB, DarcyDorian! :D

We ask that our users show their progress (work thus far or thoughts on how to begin) when posting questions. This way our helpers can see where you are stuck or may be going astray and will be able to post the best help possible without potentially making a suggestion which you have already tried, which would waste your time and that of the helper.

Assuming you don't know how to begin, we will need the following formula:

[box=green]
The Normal Distribution

$z$-score for an $x$-value: $$z=\frac{x-\mu}{\sigma}$$[/box]

Now, we are given $x=9$, $\mu=16.8$ and $\sigma=2.3$, so can you use the above formula to compute $z$ (the standard score)? :)
 
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Suppose ,instead of the usual x,y coordinate system with an I basis vector along the x -axis and a corresponding j basis vector along the y-axis we instead have a different pair of basis vectors ,call them e and f along their respective axes. I have seen that this is an important subject in maths My question is what physical applications does such a model apply to? I am asking here because I have devoted quite a lot of time in the past to understanding convectors and the dual...
Thread 'Imaginary Pythagorus'
I posted this in the Lame Math thread, but it's got me thinking. Is there any validity to this? Or is it really just a mathematical trick? Naively, I see that i2 + plus 12 does equal zero2. But does this have a meaning? I know one can treat the imaginary number line as just another axis like the reals, but does that mean this does represent a triangle in the complex plane with a hypotenuse of length zero? Ibix offered a rendering of the diagram using what I assume is matrix* notation...
Back
Top