What does the notation "population proportion p = n:m" mean in statistics? I looked everywhere (Google, this forum, KhanAcademy, etc.) and couldn't figure it out.
What does the notation "population proportion p = n:m" mean in statistics?
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statistics
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0can you give us some context? – 2017-01-21
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0It perhaps refers to a ratio: writing $n:m$ is the same as $\frac{n}{m}$. – 2017-01-21
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A real life example of using ratios is in aspect ratios for monitors and televisions. One of the most common aspect ratios is $16:9$. This means that the horizontal length of the monitor is $\frac{16}{9}$ times bigger than the vertical length. Such resolutions include $1920 \times 1080$, $1280 \times 720$. If you simplify $\frac{1920}{1080}$ and $\frac{1280}{720}$, they both simplify to $\frac{16}{9}$.
Let's say you were given a ratio of $\text{girls}:\text{boys}$ as $3:2$. This means that in this group, there are $\frac{3}{2}=1.5$ times as many girls in that group than boys. If you were given the amount of boys as $50$, you can calculate the number of girls to be $50\times \frac{3}{2}=75 \text{ girls}$.
Similarly, if you were given the number of girls to be $90$, you can divide the ratio to get the number of boys: $90/\frac{3}{2}=90\times \frac{2}{3}=60 \text{ boys}$
Hope this helps.