1d:T7f0,# Maximum Likelihood Estimator for the mean difference between two censored normally distributed samples Computes estimates of the parameters of two censored Normal samples, as well as the mean difference between the two samples. ```r NormalMeanDiffCens(censdata1, censdata2, conf.level = 0.95, null.values = c(0, 0, 1, 1)) ``` ## Arguments - `censdata1`: Observations of first sample, format as specified by `code = interval2` in `Surv`. - `censdata2`: Observations of second sample, as specified by `code = interval2` in `Surv`. - `conf.level`: Confidence level for confidence intervals. - `null.values`: Fixed values for hypothesis tests. Four-dimensional vector specifying the hypothesis for $\mu_1$, $\mu_2$, $\sigma_1$, $\sigma_2$. ## Returns A table with estimators and inference for the means and standard deviations of both samples, as well as the difference $\Delta$ between the mean of the first and second sample. Hypothesis tests are for the values in `null.values` and for the null hypothesis of no mean difference. ## References Hubeaux, S. (2013). Estimation from left- and/or interval-censored samples. Technical report, Biostatistics Oncology, F. Hoffmann-La Roche Ltd. Lynn, H. S. (2001). Maximum likelihood inference for left-censored HIV RNA data. **Stat. Med.**, 20 , 33--45. ## Author(s) Stanislas Hubeaux, stan.hubeaux@bluewin.ch Kaspar Rufibach, kaspar.rufibach@gmail.com [http://www.kasparrufibach.ch](http://www.kasparrufibach.ch) ## Examples ```r ## example with interval-censored Normal samples n <- 500 prop.cens <- 0.35 mu <- c(0, 2) sigma <- c(1, 1) set.seed(2013) ## Sample 1: LOD1 <- qnorm(prop.cens, mean = mu[1], sd = sigma[1]) x1 <- rnorm(n, mean = mu[1], sd = sigma[1]) s1 <- censorContVar(x1, LLOD = LOD1) ## Sample 2: LOD2 <- qnorm(0.35, mean = mu[2], sd = sigma[2]) x2 <- rnorm(n, mean = mu[2], sd = sigma[2]) s2 <- censorContVar(x2, LLOD = LOD2) ## inference on distribution parameters and mean difference: NormalMeanDiffCens(censdata1 = s1, censdata2 = s2) ```

NormalMeanDiffCens function