A value representing the lowest $n$ percent of the values in a data set or of the possible values of a random variable.

# Questions tagged [percentile]

151 questions

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### Is $50$th percentile equal to median?

Consider we have the $100$ distinct integers between $1$ and $100$ inclusive. The median and fiftyth percentile can be calculated as below.
Ordering: $1,2,3 ..... ,98, 99, 100$
The median is $(50+51)/2$
The $50$th percentile is $51$ ($51$ is…

Cardinal

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### Percentile Symbol - does it exist or not?

Is there a standard symbol for percentile in mathematics, much like % is used for percentage? I have trying to get the right answer but only getting conflicting answers and logic.

Karthikeyan

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**5**

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**3**answers

### What is the meaning of percentile?

I am confused by the term percentile.
Once my teacher told me that percentile means the percentage with respect to the score of the highest achiever.
This means that if in a competition I got $80$ out of $100$ and the highest score in that…

Singh

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**5**

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### What's the most accurate way to estimate a percentile from multiple partial percentiles?

There exists 3 sets of numbers. I have the 99th percentile (p99) of each set and the cardinality of the set, but not the values in the set themselves.
p99: 540, cardinality: 215
p99: 288, cardinality: 4
p99: 432, cardinality: 78
What is the most…

SGr

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**4**

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### MLE and confidence interval of $\tau$ where $P(X < \tau) = 0.98$

Let $X_1,...,X_n \sim N(u; \sigma)$ Let $\tau$ be the .98 percentile, i.e. $P(X < \tau )$ = 0.98:
Find the MLE of $\tau$:
Find an expression for an approximate $1 - \alpha$ confidence interval for $\tau$.
My Attempt is as follows:
We know the MLE…

pavybez

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**4**

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### How do you pronounce 0.1st percentile?

I'm analyzing some out of range values that are either really high (above the 99.9th percentile) or really low (below the 0.1st percentile). How would you pronounce 0.1st percentile?

ddx

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### Is there something like 700%?

I always see companies advertising their products as "700% effective " or "the product kills 900% germs".
But percent means "out of hundred". So how can the percentage be more than 100 like 700% or 900%?

pro neon

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### How to combine percentiles from different datasets

I'm trying to combine percentiles (50th and 90th) from 2 different datasets. I don't have access to the datasets at the time of combining. Apart from the percentiles I have the number of elements on each dataset.
Now, I know that any attempt at…

hortega

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### Median of Poisson Distribution

I've just taken Probability and Statistics exam and here is the question that becomes a hot debate among my friends in the classroom:
What is the median of a random variable that follows a Poisson distribution with parameter…

Venus

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### Finding Percentiles - How am I wrong?

So the problem goes:
There are 40 students and their test scores are:
30 35 43 44 47 48 54 55 56 57
59 62 63 65 66 68 69 69 71 72
72 73 74 76 77 77 78 79 80 81
81 82 83 85 89 92 93 94 97 98
Find P85.
What I did:
Using the formula…

thes4s

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**2**answers

### How do I find percentiles of data sets (Even vs odd)?

Given the following data set with an even number of values:
$100, 100, 105, 113, 129, 132, 146, 152, 176, 200$
The value representing the 30th percentile, using the formula n(p/100) where n = sample size and p = percentile, is at position 10(0.30)…

Riptyde4

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### Sequence of order statistic converges to median?

Suppose that $(X_1,...,X_N)$ be $N$ iid samples from uniform distribution. Let $X_{(n)}$ be $n$-th order statistic. It sounds natural that $X_{N/2}$ converges to the median, $1/2$. (interpret $N/2$ as the largest integer which does not exceed…

tarou2

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**3**answers

### How can I calculate revenue from cost and profit margin?

Let's say I have a profit margin of 70% and expenses of $250 can I not calculate my estimated revenue?
I'm using this formula: Profit Margin = (Revenue - Expenses) / Revenue.
I'm trying to understand what my projected revenue would be given my…

rmontgomery429

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### Why add one to the number of observations when calculating percentiles?

The CFA Quantitative Methods book uses the following formula for finding the observation in a sorted list that corresponds to a given percentile $y$ in a set of observations of size $n$:
$(n + 1)\frac{y}{100}$
It defines percentile as follows:…

dumb question

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### Why does the 90th percentile come out to be greater than the greatest number?

Why is the 90th percentile of the following numbers 0.193204884?
0.193111065
0.188885706
0.191501273
0.193298704
0.18895934
0.192364606How can the 90th percentile be greater than the greatest number in the set?
I used the formula -…

navneesi

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