I really just want to know if im understanding the question the correct way. I h
ID: 3329525 • Letter: I
Question
I really just want to know if im understanding the question the correct way. I have listed the cut off values below that I think are correct.
What are the cutoffs for the following values for determining which observations are influential
Store
Leverage (hii)
Rstudent
Cook’s D
DFFITS
1
0.2923892054
1.0881935729
0.1615357447
0.6995030288
2
0.2923892054
2.4431335021
0.6516966714
1.5704736061
3
0.0981323675
-0.182891518
0.0012782334
-0.060329302
4
0.0981323675
-1.981304066
0.1233824172
-0.653560609
5
0.0667553728
-0.926163218
0.02060666
-0.247703928
6
0.0667553728
-0.521987259
0.006755315
-0.13960638
7
0.0607989317
-1.872918444
0.0668668686
-0.476527043
8
0.0607989317
-0.158683552
0.0005727353
-0.04037389
9
0.0559953501
-1.449240952
0.0392544455
-0.352963269
10
0.0559953501
-0.752573146
0.0114598965
-0.18328952
11
0.1251477101
0.8491959416
0.0348982938
0.321182591
12
0.1251477101
0.5021760354
0.0125175037
0.1899328439
13
0.3563729116
1.964991771
0.6193702453
1.4621634436
14
0.3563729116
0.8045791277
0.1217371628
0.5986926792
15
0.0690226633
0.2113424039
0.0011622763
0.057545709
16
0.0690226633
0.2177150285
0.0012332387
0.0592808894
17
0.0801285438
-0.25675549
0.0020131298
-0.075779161
18
0.0801285438
-0.058311619
0.0001041953
-0.01721017
19
0.116654978
-0.482157267
0.0106644153
-0.175216569
20
0.116654978
0.9798340729
0.0423516451
0.3560729581
21
0.1786019656
0.8413513221
0.0521069068
0.3923229093
22
0.1786019656
-0.181896569
0.0025266429
-0.08481854
leverage (hii) : 2
rstudent (ti) :2
DFFITSi : 0.0
Cook’s Di: .1
Store
Leverage (hii)
Rstudent
Cook’s D
DFFITS
1
0.2923892054
1.0881935729
0.1615357447
0.6995030288
2
0.2923892054
2.4431335021
0.6516966714
1.5704736061
3
0.0981323675
-0.182891518
0.0012782334
-0.060329302
4
0.0981323675
-1.981304066
0.1233824172
-0.653560609
5
0.0667553728
-0.926163218
0.02060666
-0.247703928
6
0.0667553728
-0.521987259
0.006755315
-0.13960638
7
0.0607989317
-1.872918444
0.0668668686
-0.476527043
8
0.0607989317
-0.158683552
0.0005727353
-0.04037389
9
0.0559953501
-1.449240952
0.0392544455
-0.352963269
10
0.0559953501
-0.752573146
0.0114598965
-0.18328952
11
0.1251477101
0.8491959416
0.0348982938
0.321182591
12
0.1251477101
0.5021760354
0.0125175037
0.1899328439
13
0.3563729116
1.964991771
0.6193702453
1.4621634436
14
0.3563729116
0.8045791277
0.1217371628
0.5986926792
15
0.0690226633
0.2113424039
0.0011622763
0.057545709
16
0.0690226633
0.2177150285
0.0012332387
0.0592808894
17
0.0801285438
-0.25675549
0.0020131298
-0.075779161
18
0.0801285438
-0.058311619
0.0001041953
-0.01721017
19
0.116654978
-0.482157267
0.0106644153
-0.175216569
20
0.116654978
0.9798340729
0.0423516451
0.3560729581
21
0.1786019656
0.8413513221
0.0521069068
0.3923229093
22
0.1786019656
-0.181896569
0.0025266429
-0.08481854
Fit Diagnostics for Sales_IY 300o 200 100-o 208 -100 200 300 800 0.1 12001600 Predicted Value 800 1200 1600 0.2 0.3 Predicted Value Leverage 1750 1500 1250 1000 750 200 0.2 200 1250 Predicted Value 750 1750 -2 1 02 Quantile 0 5 1015 20 Observation Fit-Mean Residual 400 Observations 22 Parameters Error DF MSE R-Square 0.8087 Adj R-Square 0.7886 20 200 25251 400 a -480 -240 0 240 480 Residua 0.0 0.4 0.8 0.0 0.4 0.8 Proportion LessExplanation / Answer
DFFITS and Cook's distance are two measures to identify influential points. An observation is considered influential if the absolute value of its DFFITS value is greater than 2sqrt[(p+1)/(n-p-1)], where, n is number of observations and p is the parameter including intercept. Thus, the cutoff value is: 2sqrt[(2+1)/(22-2-1)]=0.79. Thus, observation 2 (1.57>0.79) and observation 13 (1.46>0.79) are influential.
According to Cook's distance measure, Di, if Di is greater than 0.5, the ith data point is worthy of investigation, as it might be influential. If Di is greater than 1, the ith data point is quite likely to be influential, and if Di is remarkably different from rest, then the ith point is influential. Therefore, observation 2 and observation 13 are influential points, as both Cook's D are greater than 0.5.