Overview of Mean, Median and Mode Video Lecture | Mathematics (Maths) Class 7

okay so welcome to my first video on
sadistic s-- in this video or going over
the mean median and mode the three
central tendencies the foundation of
statistics and it's really important
that you understand these core concepts
because you're going to use them
throughout the duration of your course
so let's get started right away with an
example and hopefully this will all make
more sense after we're finished
let's say we have the numbers 10 20 30
40 and another 40 and we need to find a
three central tendencies of this data
set so the mean median mode so let's
start out and let's find the mean the
mean is more commonly known as the
average so we need to find the average
of these set of numbers and in order to
find the mean you just have to add all
the numbers so let's add all our numbers
we add 10 plus 20 plus 30 plus 40 plus
40 and then we need to then we need to
divide by the total amounts of numbers
we have 1 2 3 4 5 numbers in our data
set so we need to divide by the number 5
and if we add 10 plus 20 is 30 30 plus
30 60 60 plus 40 is 100 hundred plus 40
is 140 so in our numerator we have 140
and in our denominator we have 5 140
divided by 5 is equal to 28 so our
average or our mean of this data set is
equal to 28 alright so now let's find
our median the median can be found first
what you need to do is order the numbers
from smallest to largest and this is our
we have 10 20 30 40 40 so they're
already from smallest to largest
and the median is always the number
that's right in the middle
notice how this number 30 you draw a
line through it how there's two numbers
to the left of 30 and there's two
numbers to the right of 30 so 30 is the
number that's exactly in the middle so
our median is equal to 30 and just a
quick side note the meeting is a little
different if you have a even set of
numbers let's say we had the numbers 10
20 30 40 50 and 60 notice how now that
we instead of having five numbers now we
have six and if we drew a number or if
we've trying to find the number that's
right in the middle we have them it's in
between the 30 and the 40 notice how
there is three numbers to the right of
the line and there's three numbers to
the left from so whatever this happens
you take the two numbers that are in the
middle 30 and 40 and you average them
together so 30 plus 40 divided by 2 is
equal to 35 all right so for this
particular data set the median is equal
to 35 all right so let's go back to our
original example all right so we found
our mean we found our median now let's
find our mode our mode is just the
number that occurs the most and I'll
circle the number that occurs the most
in red notice how every number occurs
once except for 40 we have 240 s so
because 40 occurs the most our mode is
equal to 40 so now we have found all our
measures of central tendency our mean is
equal
2:28 our median is equal to 30 and our
mode is equal to 40 so many people ask
me the question what is the best measure
is the mean better than the median is
the medium better the mode which measure
of central tendency should be used the
mean median or mode and I don't have an
exact answer to that question you
probably should just use your common
sense this will make a lot more sense if
I just use an example let's say for
example that you're measuring your
weight and every day every morning you
go on a weight scale and you measure
your weight so let's say one day you
measure yourself anyway a hundred pounds
and then the next day you measure
yourself and once again anyway 100
pounds
the next day you weigh a hundred pounds
fourth day you also weigh a hundred
pounds and let's say on the fifth day
let's say you weigh let's just make it
really ridiculous let's say you weigh
600 pounds on the fifth day all right
now if we found our mean for the set of
data it would be 100 plus 100 plus 100
plus 100 plus 600 divided by five and
our mean would be equal to 200 now the
median of this data set is just a number
that's right in the middle which is a
hundred so our median is equal to 100
and our mode is also going to be equal
to hundred because the number hundred
occurs the most and I think it's pretty
common sense that the meeting and the
mode are much more accurate measures of
central tendency than the mean okay that
is because this number 600 is obviously
inaccurate there must have been an error
in the wait scale or there must have
been some sort of error there's no way
you can gain 500 pounds in one day and
that really affected our me
you know you're obviously your weight is
around 100 pounds and the mean says that
your weight is the average is 200 pounds
so that's not even close the mean is
probably not a measure of central
tendency that you should use and the
median and the mode are much more
accurate much more accurate descriptions
of this data set
um so use your common sense I hope you
enjoyed this video and this give you a
better idea of mean median and mode I
will be making a video on standard
deviation next so stay tuned and until
my next one I will see you later