Question

Management of a home appliance store wants to
understand the growth pattern of the monthly sales
of a new technology device over the past two years.
The managers have recorded the relevant data in
the file P13_05.xlsx. Have the sales of this device
been growing linearly over the past 24 months? By
examining the results of a linear trend line, explain
why or why not. Please show excel formulas so I can understand.

Month	Sales (units)
1	23
2	156
3	330
4	482
5	1209
6	1756
7	2000
8	2512
9	2366
10	2942
11	2872
12	2937
13	3136
14	3241
15	3149
16	3524
17	3542
18	3312
19	3547
20	3376
21	3375
22	3403
23	3697
24	3495

Answer 1

Version:1.0 StartHTML:000000204 EndHTML:000224002 StartFragment:000101671 EndFragment:000223970 StartSelection:000102581 EndSelection:000223957 SourceURL:https://mathcracker.com/linear-regression

	Month	Sales(units)	Month*Sales(units)	Month2	Sales(units)2
	1	23	23	1	529
	2	156	312	4	24336
	3	330	990	9	108900
	4	482	1928	16	232324
	5	1209	6045	25	1461681
	6	1756	10536	36	3083536
	7	2000	14000	49	4000000
	8	2512	20096	64	6310144
	9	2366	21294	81	5597956
	10	2942	29420	100	8655364
	11	2872	31592	121	8248384
	12	2937	35244	144	8625969
	13	3136	40768	169	9834496
	14	3241	45374	196	10504081
	15	3149	47235	225	9916201
	16	3524	56384	256	12418576
	17	3542	60214	289	12545764
	18	3312	59616	324	10969344
	19	3547	67393	361	12581209
	20	3376	67520	400	11397376
	21	3375	70875	441	11390625
	22	3403	74866	484	11580409
	23	3697	85031	529	13667809
	24	3495	83880	576	12215025
SUM	300	60382	930636	4900	185370038

Based on the above table, the following is calculated:

Therefore, based on the above calculations, the regression coefficients (the slope mmm, and the y-intercept nnn) are obtained as follows:

.

Therefore, we find that the regression equation is:

Sales(units)=604.3841+152.9226Month

Graphically:

please rate my answer and comment for doubts.