Question

I have a sample size of 58 for a process improvement on reducing spending. My improvement lasted for 9 weeks, 5 weeks I collected 40 receipts of expenses before and after my process improvement I collected 18 receipts. I need to calculate the Standard deviation for the process before and then the correction after.

(before the correction 40 expenses

3/1 7.30

3/1 6.60

3/1 24.66

3/6/2019	117.42
3/12/2019	11.71
2/1/2019	59.73
2/22/2019	63.36
2/22/2019	68.16
2/1/2019	71.58
2/15/2019	83.05
2/22/2019	7.99
2/25/2019	287.68
2/22/2019	29.31
2/23/2019	27.69
2/2/2019	2.66
2/2/2019	2.66
2/4/2019	21.73
2/4/2019	33.65
2/10/2019	8.99
2/11/2019	33.10
2/5/2019	57.48
2/5/2019	24.00
2/11/2019	9.10
2/21/2019	3.10
2/27/2019	61.44
2/26/2019	8.89
2/25/2019	34.16
2/22/2019	68.10
2/21/2019	29.83
2/19/2019	10.32
2/19/2019	4.67
2/13/2019	5.53
2/13/2019	18.95
2/12/2019	4.67
2/12/2019	23.30
2/12/2019	38.40
2/9/2019	63.15
2/1/2019	29.35
2/1/2019	18.81

after the correction (18 expenses)

16-Mar	$24.00
15-Mar	$4.24
14-Mar	$10.58
14-Mar	$2.99
13-Mar	$32.21
13-Mar	$7.84
13-Mar	$2.99
11-Mar	$4.48
11-Mar	$52.32
8-Mar	$2.49
8-Mar	$6.30
7-Mar	$4.07
6-Mar	$3.32
6-Mar	$57.11
5-Mar	$4.19
5-Mar	$19.01
5-Mar	$7.99

3/4 31.69

Answer 1