desc | R Documentation |
desc()
estimates the descriptive statistics such as
Min
(Minimum), 1st Qu.
(quartile), Median
, Mean
(average), 3rd Qu.
(3rd quartile), Max
(maximum), var
(variance), std.dev
(standard deviation), coef.var
(CV or coefficient of variation) of the data set.
desc(datap, resp)
datap |
The data set |
resp |
an integer value indicating the column
in |
The desc()
function estimates the descriptive statistics,
in tables for one or more independent (exogenous) variables on
a dependent(endogenous) variable. It acts only on numerical
variables.
For example for the variable x
:
1st. quartile:
\mjsdeqnQ_1 = (n + 1) x 1/4
2nd. quartile or Median:
\mjsdeqnmd = (n + 1) x 2/4
3rd Qu.:
\mjsdeqnQ_3 = (n + 1) x 3/4
Arithmetic mean:
\mjsdeqn\barx=\frac1n \sum_i=i^n x_i
Range:
\mjsdeqnR_x = \max(x) - \min(x)
Variance
:
\mjsdeqn\sigma_x^2 = \frac\sum_i=1^n(x_i-\barx)^2n
Standard deviation:
\mjsdeqnsd_x = \sqrt\frac\sum_i (x_i - \mu)^2n
SEM or SE.mean
, the standard error of the mean is
calculated simply by taking the standard deviation and
dividing it by the square root of the sample size:
\mjsdeqnSEM_x = \fracsd(x)\sqrtn
coef.var or coefficient of variation:
\mjsdeqnCV = \fracsd(x)\barx \times 100
Returns a list of 3 objects:
Descriptive statistics1 of input data
Descriptive statistics2 of input data
A table of correlation coefficients
Ali Arminian abeyran@gmail.com
Bhattacharyya GK and Johnson RA 1997. Statistical Concepts and Methods, John Wiley and Sons, New York.
Draper N and Smith H 1981. Applied Regression Analysis, John Wiley & Sons, New York.
Neter, J, Whitmore, GA, Wasserman, W 1992. Applied Statistics. Allyn & Bacon, Incorporated, ISBN 10: 0205134785 / ISBN 13: 9780205134786.
Snedecor, G.W., Cochran, W.G. 1980. Statistical Methods. Iowa State University Press.
correlation
, multiple linear regression
,
data(dtsimp)
desc(dtsimp, 1)
data(dtraw)
desc(dtraw[, -1], 1)
data(heart)
desc(heart, 2)
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