New to JMP and struggling with Standard Deviation differences between Excel & JMP

[#1]

I'm a 20+ year user of Minitab but my company is no longer buying the licenses because of recent drastic price increases and licensing model.  Just got JMP version 17.0.0 on Friday and trying to figure out how to do some Control Charts.  My biggest issue is trying to understand how JMP is giving me a different Standard Deviation than by my manually calculating them in Excel.

When I calculate the Mean on the Data Value Column (Data Below), both Excel and JMP come up with 8.9259... 

When I calculate the Standard Deviation =STDEV.P(), Excel gives me a StDev of 7.6880 resulting in an UCL limit of 31.19.   In JMP, it is calculating an UCL of 17.88881.   What am I not doing right / considering correctly?   

This is supposed to be an IMR chart in JMP but it keeps building a C Chart so not sure if that has something to do with it. 

I like that JMP is automatically bounding the LCL at 0 since it can't be a negative.

The data points with an * are obviously "No Observed Data" at this time and in excel, I have it inject an * in the calculations to get the data.

Look forward to any insights you can provide.

Thank you!

Record	Data
1	28
2	12
3	9
4	5
5	13
6	22
7	36
8	20
9	9
10	6
11	19
12	7
13	13
14	2
15	13
16	9
17	17
18	30
19	*
20	*
21	*
22	*
23	15
24	*
25	4
26	*
27	9
28	7
29	13
30	5
31	8
32	4
33	8
34	13
35	4
36	*
37	1
38	6
39	2
40	6
41	*
42	1
43	3
44	9
45	1
46	*
47	7
48	1
49	9
50	*
51	14
52	14
53	*
54	*
55	1
56	2
57	2
58	14
59	7
60	9
61	2
62	*
63	1
64	*
65	6
66	*
67	*
68	1
69	*
70	0
71	3
72	*
73	*
74	*
75	*
76	*
77	*
78	*
79	*

[#2]

MRB,

In this instance, I do have the full population of the data based on a system just recently introduced and I will always have the population of the data available.  This is where I'll be tracking and reporting process outcomes and capabilities of specific steps in the process.

Chris

[#3]

Hi @ChrisMarkley : I don't understand; but, then again, I don't have to. I'm happy to explore this further with you if you like though.

If so, may I start with...what do you mean by "capabilities"?  Do you mean capability indices like Cpk, Ppk, etc?  Further, for what purpose are you "tracking and reporting process outcomes and capabilities of specific steps in the process"?  

[#4]

I have used both software programs for over 30 years.  I believe over time you will come to embrace JMP and how superior it is, but it is bit like learning a new language.  The graphics in JMP is superior (try Graph Builder for fun).

I've attached an old version of a transition guide.

Regarding your data set, as already established, it is the wrong data type.  You want an Individual moving range chart (IR in JMP)?  You are missing quite a few data points.  How would you like the software to handle those MR's?  Admittedly neither JMP nor Minitab do control charts correctly (for example, when the MR or  range chart is OOC, they still calculate control limits for the X-bar chart).