Statistics HELP :(Watch
b) The company fits a standby battery to its power supplies and has recently been experiencing problems with its life. The battery supplier claims that it should last for 200 hours under normal conditions as their tests show a mean life of 200 hours. The designer of the power supply is not convinced. A technician has tested 220 batteries for you and tabulated the results. The designer asks you to process them and to establish what the working life really is. Here are the figures.
Life (hrs) Number
210— 212 4
Calculate the measures of central tendency and feed your thoughts to the designer.
is that all? it says calculate the central tendency.. and feed the thoughts.. what exactly do they want?
standard deviation and inter quartile range are measures of spread
once you have calculated one of them, or both, you can comment on the battery makers claims about the mean life.
ok ive calculated the measures of tendency.. which is mean and median! ... how do I comment on that?
I have not done the calculations but it looks like the data is skewed so the median life is less than the mean.
If that's the case then typical battery life is less than the mean the manufacturer claims
Posted from TSR Mobile
measures of central tendency are simply averages such as the mean and median
as data is grouped
then mean will be estimated by using the midpoints
the median will be estimated by a Cumulative frequency graphs or interpolation.
for video tutorials go to UTUBE and type
mean of grouped data
median of grouped data
Also look atPages 20 - 24 on the link
there some worked solution there.
hope these are useful