Estimating mean? Statistics help.

Question

anonymous · Answer

attachment

anonymous · Answer

What does it mean by "Estimate the mean using an appropriate relationship" ?

campbell_st · Answer

why not find the mean of each column, then add then and divide by the number of columns... 

an alt process would be to do the same thing looking at rows. 

and another method would be to put the data into a grouped frequency table 

find the class centre and multiply by the frequency  then divide by the number of terms..

campbell_st · Answer

ok... just use the 1st row as a sample...

anonymous · Answer

@campbell_st Your number 3 method would actually give me the 'actual mean' instead of an estimate lol.

But yes, looking at just the 1st row would be a good way to estimate. Thanks, didn't think of that -.-.

anonymous · Answer

And what about d) the nature of the distribution? @campbell_st

campbell_st · Answer

no in a grouped frequency table the class centre times the frequency will give an estimate of the mean... because you are using the class centre as an estimate of the actual scores

here is an example 

|dw:1373060540593:dw|

you need every score for the actual  the class centre only gives an estimate