What is the z-score of X, if n = 20, $\mu =20$, SD =3, and X =31?

anudoneddbv
2022-07-17
Answered

What is the z-score of X, if n = 20, $\mu =20$, SD =3, and X =31?

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asked 2022-08-24

What is the z-score of X, if n = 57, $\mu =35$, SD =5, and X =13?

asked 2022-06-24

Having some issue with the concept of Z score.

When exactly do I use $Z=\frac{\overline{X}-u}{\sigma}$

and when do I use $Z=\frac{\overline{X}-u}{\frac{\sigma}{\sqrt{n}}}$

I get very confused with in what situation should be using which Z calculation. Really appreciate it to have someone explain the concept

When exactly do I use $Z=\frac{\overline{X}-u}{\sigma}$

and when do I use $Z=\frac{\overline{X}-u}{\frac{\sigma}{\sqrt{n}}}$

I get very confused with in what situation should be using which Z calculation. Really appreciate it to have someone explain the concept

asked 2022-08-13

What is the z-score of sample X, if $n=55,\text{}\mu =38,\text{}\text{St.Dev}=66,\text{}{\mu}_{X}=43$?

asked 2022-05-01

For z score, you are taking the sample value subtracting population mean and dividing it by std deviation. Is that correct so far?

Now, the "sample value" is defined by an equation. In my scenario, I have a bunch of stores that are reviewed by their customers. The customer amount varies. One store has 2 customers who give review while other store has 19 people who give reviews. For the 1st store in my example, both customers give 5/5. while the 2nd store customers, avg score given by all 19 customers is 4.

Sample value is calculated as score/customer count. So for the 1st store, it will be 5/2 while the other store will be 4/19. If I use that in z score eq. it will mean that first store is doing much better than the last store. I would like to know how to make the score "proportional""normalized""fair" etc...

Oh my many gods, I can't believe I ended like that. Thanks for pointing that out.

Now, the "sample value" is defined by an equation. In my scenario, I have a bunch of stores that are reviewed by their customers. The customer amount varies. One store has 2 customers who give review while other store has 19 people who give reviews. For the 1st store in my example, both customers give 5/5. while the 2nd store customers, avg score given by all 19 customers is 4.

Sample value is calculated as score/customer count. So for the 1st store, it will be 5/2 while the other store will be 4/19. If I use that in z score eq. it will mean that first store is doing much better than the last store. I would like to know how to make the score "proportional""normalized""fair" etc...

Oh my many gods, I can't believe I ended like that. Thanks for pointing that out.

asked 2022-08-12

What is the z-score of sample X, if $n=100,\mu =61,St.Dev.=43,\phantom{\rule{1ex}{0ex}}\text{and}\phantom{\rule{1ex}{0ex}}E\left[X\right]=98$?

asked 2022-08-19

What is the unit of a z-score?

asked 2022-05-15

$X\sim N(15,4)$

Find P( X > 18.7 | X > 11.7 ).

Attempt: Rewrite as P ( x > 18.7) - P( x > 11.7)

Using the phi function

$\varphi (1.85)-\varphi (-1.65)=(0.9678)-(0.0495)=0.9183$

Where did I go wrong?

Find P( X > 18.7 | X > 11.7 ).

Attempt: Rewrite as P ( x > 18.7) - P( x > 11.7)

Using the phi function

$\varphi (1.85)-\varphi (-1.65)=(0.9678)-(0.0495)=0.9183$

Where did I go wrong?