Calculate the mode of a sample: both modal value(s) and the corresponding frequency
maxFreq(x, na.rm = TRUE)
modeOf(x, na.rm = TRUE)A vector containing the observations.
Logical value indicating whether NA values should be removed.
The modeOf function returns the mode of x. If there
are ties, it returns a vector containing all values of x that have
the modal frequency. The maxFreq function returns the modal
frequency as a numeric value.
These two functions can be used to calculate the mode (most
frequently observed value) of a sample, and the actual frequency of the
modal value. The only complication is in respect to missing data. If
na.rm = FALSE, then there are multiple possibilities for how to
calculate the mode. One possibility is to treat NA as another
possible value for the elements of x, and therefore if NA
is more frequent than any other value, then NA is the mode; and
the modal frequency is equal to the number of missing values. This is
the version that is currently implemented.
Another possibility is to treat NA as meaning "true value unknown",
and to the mode of x is itself known only if the number of missing
values is small enough that -- regardless of what value they have -- they
cannot alter the sample mode. For instance, if x were
c(1,1,1,1,2,2,NA), we know that the mode of x is 1
regardless of what the true value is for the one missing datum; and we
know that the modal frequency is between 4 and 5. This is also a valid
interpretation, depending on what precisely it is the user wants, but
is not currently implemented.
Because of the ambiguity of how na.rm = FALSE should be interpreted,
the default value has been set to na.rm = TRUE, which differs from
the default value used elsewhere in the package.
# simple example
eyes <- c("green","green","brown","brown","blue")
modeOf(eyes)
#> [1] "green" "brown"
maxFreq(eyes)
#> [1] 2
# vector with missing data
eyes <- c("green","green","brown","brown","blue",NA,NA,NA)
# returns NA as the modal value.
modeOf(eyes, na.rm = FALSE)
#> [1] NA
maxFreq(eyes, na.rm = FALSE)
#> [1] 3
# returns c("green", "brown") as the modes, as before
modeOf(eyes, na.rm = TRUE)
#> [1] "green" "brown"
maxFreq(eyes, na.rm = TRUE)
#> [1] 2