Description Usage Arguments Value Examples

View source: R/summary_functions.R

Find the MEC projected from a lognormal distribution using methods described in EPA's Technical Support Document for Water Quality-based Toxics Control.

1 2 3 4 5 6 7 8 9 | ```
project_mec(
qual,
result,
nd = c("<", "nd", "ND"),
percentile = 0.95,
conf_level = 0.99,
nd_adjustment = 0.5,
simple_output = FALSE
)
``` |

`qual` |
A character vector containing non-detect indicator strings, e.g., "<" or "ND". The strings used to indicate censored status can be edited in the "nd" argument. |

`result` |
A numeric vector of concentration measurements. |

`nd` |
A list indicating all the censoring flags included in the dataset. Defaults to "<", "nd", and "ND". |

`percentile` |
Location on lognormal distribution to estimate the projected MEC. |

`conf_level` |
Confidence level of projected estimate. |

`nd_adjustment` |
Adjustment factor for non-dectect values. Non-detect values (as indicated in qual vector) are multiplied by nd_adjustment factor; i.e. result * nd_adjustment. Typically, method detection limits or reporting limits are used as result values for non-detects. |

`simple_output` |
Logical value. If TRUE, the output columns are concatenated into a single character string (e.g., "<0.2") which can be useful for constructing summary tables. |

Dataframe with a qualifier column (character) and a MEC column (numeric).

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | ```
# Find observed MEC
cen_result <- c(rep("", 10), rep("<", 10))
result <- 1:20
project_mec(cen_result, result)
# Demonstrate simplified output
cen_result <- rep("<", 20)
project_mec(cen_result, result, simple_output = TRUE)
# Define a set of custom non-detect flags
cen_result <- c(rep("non-detect", 5), rep("<", 10), rep("mdl", 5))
project_mec(cen_result, result, nd = c("non-detect", "<", "mdl"))
# Change the substitution multiplier used for non-detect values
cen_result <- c(rep("<", 5), rep("", 15))
result <- c(101:120)
project_mec(cen_result, result) # Use default 0.5 multiplier
# Use 1.0 multiplier (equivalent to using MDL)
project_mec(cen_result, result, nd_adjustment = 1.0)
# Use 0.0 multiplier (equivalent to zero substitution)
project_mec(cen_result, result, nd_adjustment = 0)
``` |

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