SOLUTION: The department store manager has prepared data on the sales volume of product A for 28 days (sample): 3;1;2;0;2;0;1;3;1;2;5;0;1;2; 0;0;1;1;0;1;2;3;5;2;1;0;3;0. *Calculate the sa

Question 1202552: The department store manager has prepared data on the sales volume of product A for 28 days (sample):
3;1;2;0;2;0;1;3;1;2;5;0;1;2;
0;0;1;1;0;1;2;3;5;2;1;0;3;0.
*Calculate the sample mean and variance.
Found 2 solutions by mananth, math_tutor2020:
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
0,0,1,1,0,1,2,3,5,2,1,0,3,0,3,1,2,0,2,0,1,3,1,2,5,0,1,2 values (28)
Sum = 42, count =28 mean = 42/28 =1.5
subtract mean from each value above we get
-1.5, -1.5, -0.5, -0.5, -1.5, -0.5, 0.5, 1.5, 3.5, 0.5, -0.5, -1.5, 1.5, -1.5, 1.5, -0.5, 0.5, -1.5, 0.5, -1.5, -0.5, 1.5, -0.5, 0.5, 3.5, -1.5, -0.5, 0.5
Take the square of of each of the above difference
2.25, 2.25, 0.25, 0.25, 2.25, 0.25, 0.25, 2.25, 12.25, 0.25, 0.25, 2.25, 2.25, 2.25, 2.25, 0.25, 0.25, 2.25, 0.25, 2.25, 0.25, 2.25, 0.25, 0.25, 12.25, 2.25, 0.25, 0.25
Total the values =55
55/28 = 1.964285714 = variance

1.401529776 = standard deviation.

Answer by math_tutor2020(3817) (Show Source): You can put this solution on YOUR website!

The tutor @mananth has the right idea.

However, we won't divide by n = 28, because this computes the population variance.

Instead we divide by n-1 = 28-1 = 27 to determine the sample variance.

The sample variance is 55/27 = 2.037 approximately.

Helpful calculator:
https://www.calculatorsoup.com/calculators/statistics/variance-calculator.php
Separate the data values with a comma and not a semicolon.
Feel free to explore other such calculators.
A spreadsheet is another good option.

This article talks about the sample variance on a TI84
https://www.statology.org/sample-variance-ti-84/

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