Any math or statistics expert out there?

[AngelOfDeath]

I'm trying to figure out this statistical problem that is in my book. It's about testing the null hypothesis.
Here are the facts:

The claimed population mean is 1100
The sample mean is 923.62
The sample standard deviation is 84.64
The number of samples is 100.
Population standard dev is not given.

So i guess im proving or disproving the claim that 1100 is the true population mean.
Ho: μ=1100
H1: μ≠1100

I tried using the t statistic formula but it ended up with a wierd answer.
I know there are some smart guys out there so please help me with this. I haven't had much sleep now. Thanks.

[pawel]

What is the question? What does it ask you to test for?

test stat = (923.62 - 1100)/(84.64/(100)^0.5) should be the equation, I think. It's going to be negative, somewhere around -20, so you would most likely reject Ho.

[AngelOfDeath]

The question I guess is prove or disprove the claim of $ 1100 is the income per month. At 1% significance level by the way.

I got -20.84 using t-stat. I'm skeptical since this is such a huge number. I don't know if i did it right.

Do you think it's feasable that that is the answer? Thanks for your answer.

[pawel]

Sure, it can be -20 or something. It just means your Ho is really off. If you look at your question, you have a relatively large sample, and your x bar is about two standard deviations away from your supposed μ, which suggests there is something wrong with the Ho being μ=1100.

[AngelOfDeath]

What do you call the formula that you used? I presume that it is the t test and not the z test, since the standard dev population is unknown? Is this right?

Thanks for helping by the way. Are you a statistician or a teacher? Thanks again.

[Koss]

...What in the Flying F**k are you guys talking about??

[Powerslave214]

I hate it when my Ho is off ;-)

[carlos grijalva]

maths is fun

[j.arledge]

Originally Posted by carlos grijalva

maths is fun

I am not much good at math but 1100 seems reasonable figure unless i didn't understand the terminology and or question


numbers . Like why are there so many ?

Oh i got a physics problem for you.

BOIL an egg to perfection without costly egg timers

pop the egg into
boiling water and driving away from your home at exactly 60 mph. After 3
miles, phone your wife and tell her to take the egg out the pan.
Physics in action .

[Koss]

Great...so you run through traffic lights and stop signs, hitting pedestrians and small puppies, wasting precious gas and running up your cell phone bill, all because you have a craving for a boiled egg, and are too cheap to buy an egg timer....

...makes sense.

[pawel]

Originally Posted by Powerslave214

I hate it when my Ho is off ;-)

Don't we all, don't we all...

[iumentum]

This reminds me that i hate statistics...

[j.arledge]

Originally Posted by Koss

Great...so you run through traffic lights and stop signs, hitting pedestrians and small puppies, wasting precious gas and running up your cell phone bill, all because you have a craving for a boiled egg, and are too cheap to buy an egg timer....

...makes sense.

it's the American way