Mathematics Stack Exchange
Mathematics Stack Exchange

Questions tagged [standard-deviation]

In Probability and Statistics, the standard deviation of a statistical population or data set is a measure of how much variation or dispersion exists from its average value. It is defined as the square root of the variance. Use this tag alongside (statistics).

In Probability and Statistics, the standard deviation of a statistical population or data set is a measure of how much variation or dispersion exists from its average value. It is defined as the square root of the variance.

1413 questions
0
votes
1 answer

Will calculating standard deviations from percentages give different results to claculating them from the raw data?

I'll start off by saying I am not a mathematician, nor have I studied maths for many years, so please keep the answers simple :) I am working with data that has a geographical context. So assume I have data about an area 10km by 10km. My data is…
Dan_h_b
  • 103
0
votes
0 answers

Standard deviation of a normal distribution with arbitrary points

Good day! Im currently dealing with the formula in determining the expected number of real roots of random algebraic polynomial,,, and I want to solve for the formula of the standard deviation. I have collected a number of real roots from 100,000…
rosa
  • 1,171
0
votes
2 answers

Standard deviation question - how did they get this answer!? so confused!?

Odwalla’s OJ is packaged in $250$ ml bottles and has a process standard deviation of $10$ ml. In monitoring the fill process, $6$ samples (of $25$ bottles each) were collected and averaged: $249$ $252$ $253$ $248$ $245$ $253$ What is the total…
Little Black Dog
  • 161
0
votes
1 answer

Does the value of a standard deviation have any meaning

I understand that the standard deviation corresponds deviance from the mean but does the actual value of the standard deviation have any direct meaning? For example if you have a $\sigma$ of 10, does 10 mean anything by itself? (relative to the…
CobaltHex
  • 173
-1
votes
2 answers

Standard Deviation result wrong or right

I made two scripts in PHP to calculate the standard deviation. But I am not sure if it works correctly both of my scripts have different results. first script 1,2,3,4,5,1 = 1.5 second script 1,2,3,4,5,1 = 1.49 or are both wrong if so please tell me…
Raymond the Developer
  • 103
-1
votes
1 answer

Calculating Standard Deviation from Average and Total Values

I'm looking to calculate the standard deviation when all I have is the average alongside how many records there are. In my dataset I have been provided, I can see an average value which is reflected in the top 5 of the dataset provided. How can I…
Chazmondo
  • 1
-1
votes
1 answer

Probability distribution; what is probability that i wont spend more than 75% of the customers

Very simple question but I am kinda stuck. Suppose that evidence in sales data suggests that average amount spent by a customer in a store averages 35.60 with a standard deviation of 16.4. A sample of 64 customers is selected at random for study. I…
Stormxlr
  • 3
  • 2
-1
votes
1 answer

Standard Deviation comparison

Currently i am working on my master thesis. I performed a research of the weather on sales. Different weather types are included in the model such as sunshine duration, duration of rainfall and level of humidity. I performed the analysis 3 times,…
Thesis91
  • 1
-1
votes
1 answer

find sub-group of any given number

sorry i couldn't think of better title so i have a number lets say 13(variable) and by dividing it to 5 (constant) i get my groups (3 in this example ) 1 => 1-5 2 => 6-10 3 => 11-13 now i want to know group of each number between 1-13 groups =…
max
  • 101
-2
votes
1 answer

Can two standard deviation be a negative number?

Given a simple data set, the two standard deviation is calculated as a negative number. Shouldn't the standard deviations (min or max) be within the range of the data set? My data set: 2 31 32 22 10 43 12 46 48 51 51 52 82 88 10 01 07 12 31 40 15…
picolo
  • 101
-2
votes
1 answer

standard deviation and coefficient of varriation

A sample of 18 employees at a company is monitored to see how long they break for lunch on a particular day. The following data is the lunch break (in minutes) for each worker: ,25 ,25 ,32 ,45 ,22 ,34 ,56 ,51 ,35 ,30 ,33 ,38 ,44 ,31 ,48 ,36 ,26 ,36…
Rajat Sachdeva
  • 1
1 2 3 4 5 6 7
8