Nonparametric Tests
Jonckheere-Terpstra Test Table: Exact Critical Values of J
Exact critical values for the Jonckheere-Terpstra test for an ordered trend across groups, such as increasing dose.
- k = 3 to 6 groups
- Exact values
- Unequal sizes in calculator
Jonckheere-Terpstra Table
Jump to a value of k below. Rows: subjects per group · Columns: one-tailed α · Cells: critical J. Reject H₀ if J ≥ the cell.
k = 3 groups
| One-tailed α → n per group ↓ | 0.1 | 0.05 | 0.025 | 0.01 | 0.005 | 0.001 |
|---|---|---|---|---|---|---|
| 2 | 10 | 11 | 12 | — | — | — |
| 3 | 20 | 22 | 23 | 25 | 25 | 27 |
| 4 | 34 | 36 | 38 | 40 | 42 | 45 |
| 5 | 51 | 54 | 57 | 60 | 62 | 66 |
| 6 | 71 | 75 | 79 | 83 | 86 | 92 |
| 7 | 95 | 100 | 105 | 110 | 114 | 121 |
| 8 | 121 | 128 | 134 | 140 | 145 | 154 |
| 9 | 152 | 160 | 166 | 174 | 180 | 190 |
| 10 | 185 | 194 | 202 | 212 | 218 | 230 |
k = 4 groups
| One-tailed α → n per group ↓ | 0.1 | 0.05 | 0.025 | 0.01 | 0.005 | 0.001 |
|---|---|---|---|---|---|---|
| 2 | 18 | 19 | 21 | 22 | 23 | 24 |
| 3 | 37 | 40 | 42 | 44 | 45 | 48 |
| 4 | 63 | 67 | 70 | 73 | 76 | 81 |
| 5 | 95 | 100 | 105 | 110 | 114 | 120 |
| 6 | 134 | 141 | 147 | 154 | 158 | 167 |
| 7 | 179 | 188 | 196 | 204 | 210 | 222 |
| 8 | 231 | 242 | 251 | 262 | 269 | 283 |
| 9 | 290 | 302 | 313 | 326 | 334 | 351 |
| 10 | 354 | 369 | 382 | 397 | 407 | 427 |
k = 5 groups
| One-tailed α → n per group ↓ | 0.1 | 0.05 | 0.025 | 0.01 | 0.005 | 0.001 |
|---|---|---|---|---|---|---|
| 2 | 28 | 30 | 32 | 33 | 35 | 37 |
| 3 | 59 | 62 | 65 | 69 | 71 | 75 |
| 4 | 100 | 106 | 110 | 116 | 119 | 126 |
| 5 | 153 | 160 | 167 | 174 | 179 | 189 |
| 6 | 216 | 226 | 235 | 244 | 251 | 264 |
| 7 | 290 | 303 | 313 | 325 | 334 | 350 |
| 8 | 375 | 390 | 403 | 418 | 428 | 449 |
| 9 | 470 | 488 | 504 | 522 | 534 | 558 |
| 10 | 576 | 597 | 615 | 636 | 650 | 679 |
k = 6 groups
| One-tailed α → n per group ↓ | 0.1 | 0.05 | 0.025 | 0.01 | 0.005 | 0.001 |
|---|---|---|---|---|---|---|
| 2 | 40 | 43 | 45 | 47 | 49 | 52 |
| 3 | 85 | 90 | 94 | 98 | 101 | 107 |
| 4 | 147 | 154 | 160 | 167 | 171 | 181 |
| 5 | 224 | 234 | 242 | 252 | 259 | 272 |
| 6 | 317 | 330 | 342 | 354 | 363 | 381 |
| 7 | 427 | 443 | 457 | 474 | 484 | 507 |
| 8 | 552 | 572 | 589 | 609 | 623 | 650 |
| 9 | 693 | 717 | 738 | 761 | 777 | 810 |
| 10 | 850 | 878 | 902 | 930 | 949 | 987 |
Tip: click any value to highlight its row and column.
How to read this table
- Order the groups by the hypothesised trend (for example placebo, low, middle, high dose).
- For every pair of groups i < j, count the pairs of observations where the value in the later group is larger (ties count ½). J is the sum of these counts.
- Reject H₀ in favour of an increasing trend if J is greater than or equal to the table value. For unequal group sizes, use the calculator.
Worked example
A study gives placebo, low dose and high dose to 5 patients each, and the counts of increasing pairs sum to J = 56. In the k = 3 table, row 5, α = 0.05 gives 54, so there is a significant increasing trend at the 5% level.
Click the underlined links to highlight the value in the table.
Calculator
For values between the rows and columns of the table. Results update as you type.
Formula and how the values were computed
Under H₀ the J statistic is distributed as a sum of independent Mann-Whitney statistics, and its exact distribution is the normalised q-multinomial coefficient, computed exactly. Each entry is the smallest J with P(J ≥ j) ≤ α.
Frequently asked questions
Why not just use Kruskal-Wallis?
Kruskal-Wallis tests for any difference and ignores the order of the groups. When the alternative is a monotone trend, Jonckheere-Terpstra is considerably more powerful.
Is this a test of dose-response?
Yes, it is a common nonparametric test of a monotone dose-response. For binary outcomes the Cochran-Armitage trend test plays the same role.