I'm missing something so simply PLEASE HELP

Hi everyone I'm doing what should be the simplest part of Statistics 1, but for some reason my calculator refuses to correctly give the mean as 2.8, and instead says 3.5. I've checked a hundred times that I've inputted the data correctly but as soon as I press XBar it gives the wrong value. If someone could help that'd be great.... What am I doing wrong?

Reply 1

username878045

17

a) Heard of screen-shotting?

b) Try doing the calculation manually and you'll get 2.8. I couldn't say where you're going wrong using your calculator's stats functions.

Reply 2

Smaug123

15

Original post by TheDimpleboy

Hi everyone I'm doing what should be the simplest part of Statistics 1, but for some reason my calculator refuses to correctly give the mean as 2.8, and instead says 3.5. I've checked a hundred times that I've inputted the data correctly but as soon as I press XBar it gives the wrong value. If someone could help that'd be great.... What am I doing wrong?

I did it in my head in about fifteen seconds. It's 2.8. I don't have your calculator here so I don't know what you're doing with it. I would guess that you're missing out the ten zero-data-points from your calculation - that would give an answer 3.5.

Reply 3

benplumley

11

It's pretty bad practice to use the calculator function to work out statistical measures (mean, standard deviation, rmsd etc). If you use the calculator in an exam, unless it explicitly states 'use your calculator to', there's a chance you'll lose method marks. Better to learn the formulae.

Reply 4

TheDimpleboy

OP

4

I wouldn't have used it if it wasn't for the fact that I need to work out SD too, and my calculator gives the value of 2.29, where as the MS says 2.24 to 2.27..... any ideas what could be going wrong ?

Reply 5

benplumley

11

Original post by TheDimpleboy

I wouldn't have used it if it wasn't for the fact that I need to work out SD too, and my calculator gives the value of 2.29, where as the MS says 2.24 to 2.27..... any ideas what could be going wrong ?

Yes. Read my last post. I'm not writing it out again.

Reply 6

Smaug123

15

Original post by TheDimpleboy

I wouldn't have used it if it wasn't for the fact that I need to work out SD too, and my calculator gives the value of 2.29, where as the MS says 2.24 to 2.27..... any ideas what could be going wrong ?

Interesting. Omitting the zero data points gives 3.5 as the mean, but 1.99 as the standard deviation, so your error is not what I thought it was.

Reply 7

TheDimpleboy

OP

4

Original post by benplumley

Yes. Read my last post. I'm not writing it out again.

Well I appreciate you're telling me to do it manually, I'm just a bit worried both the calculators I have are making the same mistake, and the data is inputted correctly (even the zero points).