Question

Charity Donations   FOR 3.1 and 3.2

A random sample of 30 large companies in the United States shows the amount, in millions of dollars, that each company donated to charity for a specific year.  This is the same data set as the one in #2, but this time find the mean, variance, and standard deviation for the data set

26        25        19        31        14        48        85        43        25        46                   

58        34        41        12        27        15        53        16        63        82                   

56        75        19        26        88        57        21        52        17        23

Please explain and show work I am highly confused thank you!

Answer 1

Mean value is

Create the following table.

data	data-mean	(data - mean)2
26	-13.9	193.21
25	-14.9	222.01
19	-20.9	436.81
31	-8.9	79.21
14	-25.9	670.81
48	8.1	65.61
85	45.1	2034.01
43	3.1	9.61
25	-14.9	222.01
46	6.1	37.21
58	18.1	327.61
34	-5.9	34.81
41	1.1	1.21
12	-27.9	778.41
27	-12.9	166.41
15	-24.9	620.01
53	13.1	171.61
16	-23.9	571.21
63	23.1	533.61
82	42.1	1772.41
56	16.1	259.21
75	35.1	1232.01
19	-20.9	436.81
26	-13.9	193.21
88	48.1	2313.61
57	17.1	292.41
21	-18.9	357.21
52	12.1	146.41
17	-22.9	524.41
23	-16.9	285.61

Find the sum of numbers in the last column to get.

So Variance value is

So standard deviation is