strat_mean: Calculate stratified mean biomass and abundance

In andybeet/survdat: Tools for working with NEFSC survey data

Calculate stratified mean biomass and abundance

Description

Calculates the stratified mean biomass and abundance. Also calculates the associated variance and standard error.

Usage

strat_mean(
  prepData,
  groupDescription = "SVSPP",
  filterByGroup = "all",
  mergesexFlag = T,
  seasonFlag,
  areaDescription,
  poststratFlag
)

Arguments

prepData	Data table. NEFSC survey data generated by get_survdat_data and modified by strat_prep.
groupDescription	Character string. Column of prepData which contains the groups (e.g. "SVSPP") on which the means are based.
filterByGroup	Character or numeric vector. Set of groups to subset from groupDescription. The default "all" will calculate means for all groups.
mergesexFlag	Boolean. Logical value to merge sexed species such as dogfish.
seasonFlag	Boolean. Logical value to merge seasons (F) or keep them separate (T).
areaDescription	Character String. Column name from areaPolygon that contains the strata designations.
poststratFlag	Boolean. Logical value indicating whether the original strata design was used or not. Changes the calculation for the variance for post-stratified uses of survey data.

Value

Returns a table with stratified mean biomass and abundance for each group indicated by the groupDescription. In addition, the variance and standard error for both means are provided.

See Also

Other survdat: calc_stratified_mean(), calc_swept_area(), get_area(), get_length_weight(), get_survdat_clam_data(), get_survdat_data(), get_survdat_scallop_data(), post_strat(), swept_area()

Examples

## Not run: 
# Called internally

## End(Not run)

andybeet/survdat documentation built on Nov. 9, 2023, 10:11 a.m.