如何比较r中不同组的nls参数

Question

我有一个这样的数据集

<表类> iu 示例 观察 tbody><<tr>1.5625s0.3121.5625s0.3023.125s0.3353.125s0.3336.25s0.4236.25s0.39112.5s0.56212.5s0.5625s0.8425s0.84350s1.20250s1.185100s1.408100s1.338200s1.42200s1.371.5625t0.3171.5625t0.3133.125t0.3453.125t0.3436.25t0.4136.25t0.40412.5t0.57712.5t0.55725 t0.86325 t0.86250t1.2250t1.197100t1.395100t1.364200t1.425200t1.415

感谢@akrun。在我把csf_1$sample转换成因子后，我终于得到了我想要的。

csf_1[, 2] <- as.factor(c(rep("s", 16), rep("t", 16)))
nlm_1 <- nls(obs ~ (a - d) / (1 + (iu / c[sample]) ^ b) + d, data = csf_1, start = list(a = 0.3, b = 1.8, c = c(25, 25), d = 1.4))
summary(nlm_1)
Formula: obs ~ (a - d)/(1 + (iu/c[sample])^b) + d
Parameters:
Estimate Std. Error t value Pr(>|t|)
a   0.315874   0.008102   38.99   <2e-16 ***
b   1.833303   0.068432   26.79   <2e-16 ***
c1 26.075317   0.656779   39.70   <2e-16 ***
c2 25.114050   0.632787   39.69   <2e-16 ***
d   1.447901   0.011518  125.71   <2e-16 ***
---
Signif. codes:
0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
Residual standard error: 0.02015 on 27 degrees of freedom
Number of iterations to convergence: 4
Achieved convergence tolerance: 6.225e-06