Answer:
You look at your graph and or chart and start to make note
Your looking for the following tyoe data
1-5, 5-10 etc such distribution is usually done on y axes for histograms and x axes for all other graphs.
If there is a group data or frequency then you need to multiply the highest group data ie) from 0-5 it is 2.5
Then 2.5 times the actual frequency which is in the chart = say it says 4
Then 2.5 x 4 = 10
Then do the same for 5-10 = 7.5 midpoint
7.5 x frequency of 2 = 15 and so on
Then 10-15 = 12.5 midpoint you show this by 10+15/2 = 12.5 frequency of 12.5 could be 6 as in example so 6 x 12.5 = 72 etc...
When you get all totals 10+ 15+ 72 in the fx bar you cna plot on graph and then see how many have a grade lower than 80
For histograms we dont do midpoint we do highest value then times it by frequency and so our grades for 0-5 = 5
and frequency is the number of students that got such mark so we do 5 x 4 = 20 and so on then divide this number by 5 again showing that 5 students got 5 or under
and keep adding these up, the reason we would need the fx totals ie) 20 for 0-5 is that you cna map it in a histogram by adding the number below it say its 0-5 = 5 and 5 x 4 = 20
but instead of doing separately thereafter 0-5 we just add the frequency amount to 20 so if its 5-10 = 10 then we get 10 x 2 = 20 and from 20 + 20 = 40
If no frequency was given we do 5 + 10 + 15 etc. until we get to our frequency that way.
Then after adding them all up we can use this amount to get our mean etc.
and to find how many are less than 80 if histograms boxes are shown we have to distribute from how many we know as total being first one 0-5 = 5 and count 5 into the box to see the frequency there.
Say the box is 25 little boxes we know then that 25/5 = 5 so the rate of frequency is 5 for each and that each box has the same frequency or the same distribution depending if frequency is shown a different way or not.
IF its box plot then the middle line is the median and you know its exactly half of frequency and can therafter work out quartiles and count down from 80 either using the given 79 number to the set start number at start of the whiskers.
Step-by-step explanation:
