Need help with this problem

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Student117

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Hello,

I am needing some help with this problem

Is it possible to work this out in excel? If so can someone walk me through the steps?

If it’s not can someone walk me through on how to answer it and tell me the answer for it? Thank you
 

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What does "work this out" mean? It's a standard definition of a Confidence Interval. Set up the parameters and have at it.
 
tkhunny said:
What does "work this out" mean? It's a standard definition of a Confidence Interval. Set up the parameters and have at it.
Click to expand...

Ok so how do I do that? And what are the steps? Am I able to work the formula into excel??? If so what are the steps. I’m clueless
 
All you've given is a general formula for a confidence interval. There's no problem to solve until you give us some data, so we know what you are starting with and what you are looking for.

Please make it possible for us to help you, by stating an actual problem you need to solve, and telling us what you know about it that we can use in an answer. You are violating just about everything in our submission guidelines! (Well, at least the main points.)
 
Dr.Peterson said:
All you've given is a general formula for a confidence interval. There's no problem to solve until you give us some data, so we know what you are starting with and what you are looking for.

Please make it possible for us to help you, by stating an actual problem you need to solve, and telling us what you know about it that we can use in an answer. You are violating just about everything in our submission guidelines! (Well, at least the main points.)
Click to expand...


I’m not trying to violate anything. That was simply all I was given. And to see if I Could produce the formula using excel.
 
What I mean by "violate" is that we ask you to give the entire problem, and what you are able to do with it, and you didn't. If you're saying you gave us everything you were given, and you have been taught nothing about the topic, then THEY (whoever they are) are doing something wrong.

Can you at least tell us the context of your question? Is this an assignment you were given? If not, do you have some particular goal? Anything else you can tell us, can help us know how to answer effectively.

One way or another, you have to tell us what the inputs are, in order to say anything about doing something in Excel.

But let's see what I can say, with no context.

What you gave us was the inequality [MATH]\overline{x} - z_{\alpha/2}\cdot\frac{\sigma}{\sqrt{n}}\lt\mu\lt\overline{x} + z_{\alpha/2}\cdot\frac{\sigma}{\sqrt{n}}[/MATH]. This is not exactly "a formula"; it says that [MATH]\mu[/MATH] will be between two numbers. So my first comment is that all you can do is to calculate those two numbers, which define an interval within which [MATH]\mu[/MATH] must lie. You will have to know the meaning of those numbers, in your context.

How to calculate those numbers depends on what you are given. It will be one thing if you are given values for [MATH]\overline{x}[/MATH], [MATH]z_{\alpha/2}[/MATH], [MATH]\sigma[/MATH], and [MATH]n[/MATH]. It will be another if you are given data (from a survey, say) and have to calculate those numbers. Or, maybe you have something in between, such as [MATH]\alpha[/MATH] from which you have to calculate [MATH]z_{\alpha/2}[/MATH].

That's why we need more information.
 
Dr.Peterson said:
What I mean by "violate" is that we ask you to give the entire problem, and what you are able to do with it, and you didn't. If you're saying you gave us everything you were given, and you have been taught nothing about the topic, then THEY (whoever they are) are doing something wrong.

Can you at least tell us the context of your question? Is this an assignment you were given? If not, do you have some particular goal? Anything else you can tell us, can help us know how to answer effectively.

One way or another, you have to tell us what the inputs are, in order to say anything about doing something in Excel.

But let's see what I can say, with no context.

What you gave us was the inequality [MATH]\overline{x} - z_{\alpha/2}\cdot\frac{\sigma}{\sqrt{n}}\lt\mu\lt\overline{x} + z_{\alpha/2}\cdot\frac{\sigma}{\sqrt{n}}[/MATH]. This is not exactly "a formula"; it says that [MATH]\mu[/MATH] will be between two numbers. So my first comment is that all you can do is to calculate those two numbers, which define an interval within which [MATH]\mu[/MATH] must lie. You will have to know the meaning of those numbers, in your context.

How to calculate those numbers depends on what you are given. It will be one thing if you are given values for [MATH]\overline{x}[/MATH], [MATH]z_{\alpha/2}[/MATH], [MATH]\sigma[/MATH], and [MATH]n[/MATH]. It will be another if you are given data (from a survey, say) and have to calculate those numbers. Or, maybe you have something in between, such as [MATH]\alpha[/MATH] from which you have to calculate [MATH]z_{\alpha/2}[/MATH].

That's why we need more information.
Click to expand...
 

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Student117 said:
Hello,

I am needing some help with this problem

Is it possible to work this out in excel? If so can someone walk me through the steps?

If it’s not can someone walk me through on how to answer it and tell me the answer for it? Thank you
Click to expand...
11928

Yes you can evaluate "this" in excel. Do you know the definition of each of the terms in the expression? Please tell us the definitions - according to your text-book or class notes - of those terms (variables).
 
Ah ok. Now you have given us the actual question, we can help.

The "formula" you gave initially gives you the confidence interval that the question requires. Do you know what each of the symbols stand for?
You really don't need to use excel for this as you are given the values you need rather than raw data.
The "formula" looks a lot more complicated than it really is.
 
You are given everything you need except [MATH]z_{\alpha/2}[/MATH]. To get that in Excel, you can use the function NORM.S.INV, the inverse standard normal distribution. Do you know what alpha is?

Without Excel or a statistics program, you'd use a table.
 
Dr.Peterson said:
You are given everything you need except [MATH]z_{\alpha/2}[/MATH]. To get that in Excel, you can use the function NORM.S.INV, the inverse standard normal distribution. Do you know what alpha is?

Without Excel or a statistics program, you'd use a table.
Click to expand...
 

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By "solve it", do you mean "find the values of the lower and upper bounds of the confidence interval?

Please show what you are able to do, so we can have some idea where you need help. I have no idea of your level of knowledge of Excel, or of statistics.

Assign a cell to each given number. Can you translate the expression [MATH]\overline{x} - z\cdot\frac{\sigma}{\sqrt{n}}[/MATH] into Excel form?
 
Dr.Peterson said:
By "solve it", do you mean "find the values of the lower and upper bounds of the confidence interval?

Please show what you are able to do, so we can have some idea where you need help. I have no idea of your level of knowledge of Excel, or of statistics.

Assign a cell to each given number. Can you translate the expression [MATH]\overline{x} - z\cdot\frac{\sigma}{\sqrt{n}}[/MATH] into Excel form?
Click to expand...


I’m a novice at this lol so no I can’t
 
Please tell me what you CAN do, so I don't have to start with 1+1.

And if you know nothing at all about Excel, why do you want to use it here? It isn't necessary! You can do this better with pencil and paper and a normal distribution table.

What is the context of your question? Is this for a class, or something else? You're making me drag information out of you, which isn't the way to get help.
 
I'm assuming from post #13 that you can do this manually.
There are formulae to calculate the confidence interval built into excel, but it would be almost as easy to input your own formula. The extract below from https://support.microsoft.com/en-au...the-confidence-statistical-functions-in-excel shows 2 ways of calculating

\(\displaystyle z_{\alpha/2}*\frac{\sigma}{\sqrt n}\). You will obviously need to input your statistics.

That value then needs to be subtracted from and added to the sample mean to get the confidence interval.

1556751983620.png

Is that what you were asking?
 
Harry_the_cat said:
I'm assuming from post #13 that you can do this manually.
There are formulae to calculate the confidence interval built into excel, but it would be almost as easy to input your own formula. The extract below from https://support.microsoft.com/en-au...the-confidence-statistical-functions-in-excel shows 2 ways of calculating

\(\displaystyle z_{\alpha/2}*\frac{\sigma}{\sqrt n}\). You will obviously need to input your statistics.

That value then needs to be subtracted from and added to the sample mean to get the confidence interval.

View attachment 11968

Is that what you were asking?
Click to expand...

So is this the formula that you would use in excel to solve this?
 
Yes, this would give you the value you need to add to and subtract from your sampe mean to get the confidence interval.
 
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