freshmen taking AP stat...
the question is: Which of the following ogives represent the grades on a more difficult Algebra test? Explain how you know.
I am given two graphs w/ x-axis "grades" and y-axis... unlabeled. I don't really understand what an Ogive is to begin with. One graph is steeper than the other... i can't paste the graphs on here! Just please explain what an ogive is...
2007-01-14 08:32:20 · 4 answers · asked by Michelle 2 in Science & Mathematics ➔ Mathematics
An ogive is a cumulative frequency polygon, often presented in percentage terms. Cumulative frequencies show the running total, the frequency below each class boundary, as the example below shows. [look on website under "source".]
The ogive is then simply an XY plot of the cumulative frequencies (or cumulative percentage frequencies) against the class upper boundaries. A common mistake is to plot against the class midpoints, due to confusion with the simple frequency polygon.
The points should be connected by straight lines, not a smooth curve as taught by many textbooks. The straight line assumes that the data are uniformly distributed across the class interval - as represented on a histogram by a rectangular bar. Whilst this will almost certainly not be true, it gives an objective view that allows different people to come to common conclusions. Connecting the points by a smooth curve is subjective and will lead to different people drawing different conclusions from the data.
The main use of an ogive is to estimate percentiles. The 20th percentile is the value below which 20% of the data falls. Important percentiles are the median (50%), lower quartile (25%) and upper quartile (75%). Use the Template to see how quartiles can be estimated from the ogive.
It is difficult, although not impossible, to judge the shape of the distribution from an ogive. The ogive is probably only suitable for a technical audience.
2007-01-14 08:39:40 · answer #1 · answered by ( Kelly ) 7 · 0⤊ 0⤋
ogives are cumulative frequency curves. The means you take the number of people who got grade A and add that to the number that got grade B ..... and so on. Then you plot these sums vs the grade ranges. the more difficult test would have lower grades and thus the graph would not be as steep as an easier test
2007-01-14 08:50:10 · answer #2 · answered by LoneWolf 3 · 0⤊ 0⤋
Statistics Ogive
2016-10-31 07:21:14 · answer #3 · answered by ? 4 · 0⤊ 0⤋
AP Calculus 100%
2016-05-24 01:13:41 · answer #4 · answered by Anonymous · 0⤊ 0⤋