Two-Tailed
Test

.10

.05

.02

.01

One tailed Test

0.2

0.1

0.04

0.02

df=n-2, where n is the number of points

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

35

40

45

50

60

70

80

90

100

.988

.900

.805

.729

.669

.622 

.582

.549

.521

.497

.476

.458

.441

.426

.412

.400

.389

.378

.369

.360

.352

.344

.337

.330

.323

.317

.311

.306

.301

.296

.275

.257

.243

.231

.211

.195

.183

.173

.164

.997

.950

.878

.811

.754

.707

.666

.632

.602

.576

.553

.532

.514

.497

.482

.468

.456

.444

.433

.423

.413

.404

.396

.388

.381

.374

.367

.361

.355

.349

.325

.304

.288

.273

.250

.232

.217

.205

.195

.9995

.980

.934

.882

.833

.789

.750

.716

.685

.658

.634

.612

.592

.574

.558

.542

.528

.516

.503

.492

.482

.472

.462

.453

.445

.437

.430

.423

.416

.409

.381

.358

.338

.322

.295

.274

.256

.242

.230

.9999

.990

.959

.917

.874

.834

.798

.765

.735

.708

.684

.661

.641

.623

.606

.590

.575

.561

.549

.537

.526

.515

.505

.496

.487

.479

.471

.463

.456

.449

.418

.393

.372

.354

.325

.303

.283

.267

.254