HT: The Horvitz-Thompson Estimator

Description Usage Arguments Details Value Author(s) References See Also Examples

View source: R/HT.r

Description

Computes the Horvitz-Thompson estimator of the population total for several variables of interest

Usage

1
HT(y, Pik)

Arguments

y

Vector, matrix or data frame containing the recollected information of the variables of interest for every unit in the selected sample

Pik

A vector containing the inclusion probabilities for each unit in the selected sample

Details

The Horvitz-Thompson estimator is given by

∑_{k \in U}\frac{y_k}{{π}_k}

where y_k is the value of the variables of interest for the kth unit, and {π}_k its corresponding inclusion probability. This estimator could be used for without replacement designs as well as for with replacement designs.

Value

The function returns a vector of total population estimates for each variable of interest.

Author(s)

Hugo Andres Gutierrez Rojas hagutierrezro@gmail.com

References

Sarndal, C-E. and Swensson, B. and Wretman, J. (1992), Model Assisted Survey Sampling. Springer.
Gutierrez, H. A. (2009), Estrategias de muestreo: Diseno de encuestas y estimacion de parametros. Editorial Universidad Santo Tomas.

See Also

HH

Examples

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
############
## Example 1
############
# Uses the Lucy data to draw a simple random sample without replacement
data(Lucy)
attach(Lucy)

N <- dim(Lucy)[1]
n <- 400
sam <- sample(N,n)
# The vector of inclusion probabilities for each unit in the sample
pik <- rep(n/N,n)
# The information about the units in the sample is stored in an object called data
data <- Lucy[sam,]
attach(data)
names(data)
# The variables of interest are: Income, Employees and Taxes
# This information is stored in a data frame called estima
estima <- data.frame(Income, Employees, Taxes)
HT(estima, pik)

############
## Example 2
############
# Uses the Lucy data to draw a simple random sample with replacement
data(Lucy)

N <- dim(Lucy)[1]
m <- 400
sam <- sample(N,m,replace=TRUE)
# The vector of selection probabilities of units in the sample
pk <- rep(1/N,m)
# Computation of the inclusion probabilities
pik <- 1-(1-pk)^m
# The information about the units in the sample is stored in an object called data
data <- Lucy[sam,]
attach(data)
names(data)
# The variables of interest are: Income, Employees and Taxes
# This information is stored in a data frame called estima
estima <- data.frame(Income, Employees, Taxes)
HT(estima, pik)

############
## Example 3
############
# Without replacement sampling
# Vector U contains the label of a population of size N=5
U <- c("Yves", "Ken", "Erik", "Sharon", "Leslie")
# Vector y1 and y2 are the values of the variables of interest
y1<-c(32, 34, 46, 89, 35)
y2<-c(1,1,1,0,0)
y3<-cbind(y1,y2)
# The population size is N=5
N <- length(U)
# The sample size is n=2
n <- 2
# The sample membership matrix for fixed size without replacement sampling designs
Ind <- Ik(N,n)
# p is the probability of selection of every possible sample
p <- c(0.13, 0.2, 0.15, 0.1, 0.15, 0.04, 0.02, 0.06, 0.07, 0.08)
# Computation of the inclusion probabilities
inclusion <- Pik(p, Ind)
# Selection of a random sample
sam <- sample(5,2)
# The selected sample
U[sam]
# The inclusion probabilities for these two units
inclusion[sam]
# The values of the variables of interest for the units in the sample
y1[sam]
y2[sam]
y3[sam,]
# The Horvitz-Thompson estimator
HT(y1[sam],inclusion[sam])
HT(y2[sam],inclusion[sam])
HT(y3[sam,],inclusion[sam])

############
## Example 4
############
# Following Example 3... With replacement sampling
# The population size is N=5
N <- length(U)
# The sample size is m=2
m <- 2
# pk is the probability of selection of every single unit
pk <- c(0.9, 0.025, 0.025, 0.025, 0.025)
# Computation of the inclusion probabilities
pik <- 1-(1-pk)^m
# Selection of a random sample with replacement
sam <- sample(5,2, replace=TRUE, prob=pk)
# The selected sample
U[sam]
# The inclusion probabilities for these two units
inclusion[sam]
# The values of the variables of interest for the units in the sample
y1[sam]
y2[sam]
y3[sam,]
# The Horvitz-Thompson estimator
HT(y1[sam],inclusion[sam])
HT(y2[sam],inclusion[sam])
HT(y3[sam,],inclusion[sam])

####################################################################
## Example 5 HT is unbiased for without replacement sampling designs
##                  Fixed sample size
####################################################################

# Vector U contains the label of a population of size N=5
U <- c("Yves", "Ken", "Erik", "Sharon", "Leslie")
# Vector y1 and y2 are the values of the variables of interest
y<-c(32, 34, 46, 89, 35)
# The population size is N=5
N <- length(U)
# The sample size is n=2
n <- 2
# The sample membership matrix for fixed size without replacement sampling designs
Ind <- Ik(N,n)
Ind
# p is the probability of selection of every possible sample
p <- c(0.13, 0.2, 0.15, 0.1, 0.15, 0.04, 0.02, 0.06, 0.07, 0.08)
sum(p)
# Computation of the inclusion probabilities
inclusion <- Pik(p, Ind)
inclusion
sum(inclusion)
# The support with the values of the elements
Qy <-Support(N,n,ID=y)
Qy
# The HT estimates for every single sample in the support
HT1<- HT(y[Ind[1,]==1], inclusion[Ind[1,]==1])
HT2<- HT(y[Ind[2,]==1], inclusion[Ind[2,]==1])
HT3<- HT(y[Ind[3,]==1], inclusion[Ind[3,]==1])
HT4<- HT(y[Ind[4,]==1], inclusion[Ind[4,]==1])
HT5<- HT(y[Ind[5,]==1], inclusion[Ind[5,]==1])
HT6<- HT(y[Ind[6,]==1], inclusion[Ind[6,]==1])
HT7<- HT(y[Ind[7,]==1], inclusion[Ind[7,]==1])
HT8<- HT(y[Ind[8,]==1], inclusion[Ind[8,]==1])
HT9<- HT(y[Ind[9,]==1], inclusion[Ind[9,]==1]) 
HT10<- HT(y[Ind[10,]==1], inclusion[Ind[10,]==1]) 
# The HT estimates arranged in a vector
Est <- c(HT1, HT2, HT3, HT4, HT5, HT6, HT7, HT8, HT9, HT10)
Est
# The HT is actually desgn-unbiased
data.frame(Ind, Est, p)
sum(Est*p)
sum(y)

####################################################################
## Example 6 HT is unbiased for without replacement sampling designs
##                  Random sample size
####################################################################

# Vector U contains the label of a population of size N=5
U <- c("Yves", "Ken", "Erik", "Sharon", "Leslie")
# Vector y1 and y2 are the values of the variables of interest
y<-c(32, 34, 46, 89, 35)
# The population size is N=5
N <- length(U)
# The sample membership matrix for random size without replacement sampling designs
Ind <- IkRS(N)
Ind
# p is the probability of selection of every possible sample
p <- c(0.59049, 0.06561, 0.06561, 0.06561, 0.06561, 0.06561, 0.00729, 0.00729,
       0.00729, 0.00729, 0.00729, 0.00729, 0.00729, 0.00729, 0.00729, 0.00729, 0.00081,
       0.00081, 0.00081, 0.00081, 0.00081, 0.00081, 0.00081, 0.00081, 0.00081, 0.00081,
       0.00009, 0.00009, 0.00009, 0.00009, 0.00009, 0.00001)
sum(p)
# Computation of the inclusion probabilities
inclusion <- Pik(p, Ind)
inclusion
sum(inclusion)
# The support with the values of the elements
Qy <-SupportRS(N, ID=y)
Qy
# The HT estimates for every single sample in the support
HT1<- HT(y[Ind[1,]==1], inclusion[Ind[1,]==1])
HT2<- HT(y[Ind[2,]==1], inclusion[Ind[2,]==1])
HT3<- HT(y[Ind[3,]==1], inclusion[Ind[3,]==1])
HT4<- HT(y[Ind[4,]==1], inclusion[Ind[4,]==1])
HT5<- HT(y[Ind[5,]==1], inclusion[Ind[5,]==1])
HT6<- HT(y[Ind[6,]==1], inclusion[Ind[6,]==1])
HT7<- HT(y[Ind[7,]==1], inclusion[Ind[7,]==1])
HT8<- HT(y[Ind[8,]==1], inclusion[Ind[8,]==1])
HT9<- HT(y[Ind[9,]==1], inclusion[Ind[9,]==1]) 
HT10<- HT(y[Ind[10,]==1], inclusion[Ind[10,]==1]) 
HT11<- HT(y[Ind[11,]==1], inclusion[Ind[11,]==1])
HT12<- HT(y[Ind[12,]==1], inclusion[Ind[12,]==1])
HT13<- HT(y[Ind[13,]==1], inclusion[Ind[13,]==1])
HT14<- HT(y[Ind[14,]==1], inclusion[Ind[14,]==1])
HT15<- HT(y[Ind[15,]==1], inclusion[Ind[15,]==1])
HT16<- HT(y[Ind[16,]==1], inclusion[Ind[16,]==1])
HT17<- HT(y[Ind[17,]==1], inclusion[Ind[17,]==1])
HT18<- HT(y[Ind[18,]==1], inclusion[Ind[18,]==1])
HT19<- HT(y[Ind[19,]==1], inclusion[Ind[19,]==1]) 
HT20<- HT(y[Ind[20,]==1], inclusion[Ind[20,]==1]) 
HT21<- HT(y[Ind[21,]==1], inclusion[Ind[21,]==1])
HT22<- HT(y[Ind[22,]==1], inclusion[Ind[22,]==1])
HT23<- HT(y[Ind[23,]==1], inclusion[Ind[23,]==1])
HT24<- HT(y[Ind[24,]==1], inclusion[Ind[24,]==1])
HT25<- HT(y[Ind[25,]==1], inclusion[Ind[25,]==1])
HT26<- HT(y[Ind[26,]==1], inclusion[Ind[26,]==1])
HT27<- HT(y[Ind[27,]==1], inclusion[Ind[27,]==1])
HT28<- HT(y[Ind[28,]==1], inclusion[Ind[28,]==1])
HT29<- HT(y[Ind[29,]==1], inclusion[Ind[29,]==1]) 
HT30<- HT(y[Ind[30,]==1], inclusion[Ind[30,]==1]) 
HT31<- HT(y[Ind[31,]==1], inclusion[Ind[31,]==1])
HT32<- HT(y[Ind[32,]==1], inclusion[Ind[32,]==1])
# The HT estimates arranged in a vector
Est <- c(HT1, HT2, HT3, HT4, HT5, HT6, HT7, HT8, HT9, HT10, HT11, HT12, HT13,
         HT14, HT15, HT16, HT17, HT18, HT19, HT20, HT21, HT22, HT23, HT24, HT25, HT26, 
         HT27, HT28, HT29, HT30, HT31, HT32)
Est
# The HT is actually desgn-unbiased
data.frame(Ind, Est, p)
sum(Est*p)
sum(y)

################################################################
## Example 7 HT is unbiased for with replacement sampling designs
################################################################

# Vector U contains the label of a population of size N=5
U <- c("Yves", "Ken", "Erik", "Sharon", "Leslie")
# Vector y1 and y2 are the values of the variables of interest
y<-c(32, 34, 46, 89, 35)
# The population size is N=5
N <- length(U)
# The sample size is m=2
m <- 2
# pk is the probability of selection of every single unit
pk <- c(0.35, 0.225, 0.175, 0.125, 0.125)
# p is the probability of selection of every possible sample
p <- p.WR(N,m,pk)
p
sum(p)
# The sample membership matrix for random size without replacement sampling designs
Ind <- IkWR(N,m)
Ind
# The support with the values of the elements
Qy <- SupportWR(N,m, ID=y)                 
Qy
# Computation of the inclusion probabilities
pik <- 1-(1-pk)^m
pik
# The HT estimates for every single sample in the support
HT1 <- HT(y[Ind[1,]==1], pik[Ind[1,]==1])
HT2 <- HT(y[Ind[2,]==1], pik[Ind[2,]==1])
HT3 <- HT(y[Ind[3,]==1], pik[Ind[3,]==1])
HT4 <- HT(y[Ind[4,]==1], pik[Ind[4,]==1])
HT5 <- HT(y[Ind[5,]==1], pik[Ind[5,]==1])
HT6 <- HT(y[Ind[6,]==1], pik[Ind[6,]==1])
HT7 <- HT(y[Ind[7,]==1], pik[Ind[7,]==1])
HT8 <- HT(y[Ind[8,]==1], pik[Ind[8,]==1])
HT9 <- HT(y[Ind[9,]==1], pik[Ind[9,]==1])
HT10 <- HT(y[Ind[10,]==1], pik[Ind[10,]==1])
HT11 <- HT(y[Ind[11,]==1], pik[Ind[11,]==1])
HT12 <- HT(y[Ind[12,]==1], pik[Ind[12,]==1])
HT13 <- HT(y[Ind[13,]==1], pik[Ind[13,]==1])
HT14 <- HT(y[Ind[14,]==1], pik[Ind[14,]==1])
HT15 <- HT(y[Ind[15,]==1], pik[Ind[15,]==1])
# The HT estimates arranged in a vector
Est <- c(HT1, HT2, HT3, HT4, HT5, HT6, HT7, HT8, HT9, HT10, HT11, HT12, HT13,
         HT14, HT15)
Est
# The HT is actually desgn-unbiased
data.frame(Ind, Est, p)
sum(Est*p)
sum(y)

Example output

The following objects are masked from Lucy:

    Employees, ID, Income, Level, SPAM, Taxes, Ubication, Zone

[1] "ID"        "Ubication" "Level"     "Zone"      "Income"    "Employees"
[7] "Taxes"     "SPAM"     
                [,1]
Income    1061793.39
Employees  153895.08
Taxes       31174.96
The following objects are masked from data (pos = 3):

    Employees, ID, Income, Level, SPAM, Taxes, Ubication, Zone

The following objects are masked from Lucy:

    Employees, ID, Income, Level, SPAM, Taxes, Ubication, Zone

[1] "ID"        "Ubication" "Level"     "Zone"      "Income"    "Employees"
[7] "Taxes"     "SPAM"     
                [,1]
Income    1045679.50
Employees  160153.97
Taxes       26241.48
[1] "Ken"    "Leslie"
[1] 0.34 0.27
[1] 34 35
[1] 1 0
     y1 y2
[1,] 34  1
[2,] 35  0
         [,1]
[1,] 229.6296
         [,1]
[1,] 2.941176
         [,1]
y1 229.629630
y2   2.941176
[1] "Yves" "Yves"
[1] 0.58 0.58
[1] 32 32
[1] 1 1
     y1 y2
[1,] 32  1
[2,] 32  1
         [,1]
[1,] 110.3448
         [,1]
[1,] 3.448276
         [,1]
y1 110.344828
y2   3.448276
      [,1] [,2] [,3] [,4] [,5]
 [1,]    1    1    0    0    0
 [2,]    1    0    1    0    0
 [3,]    1    0    0    1    0
 [4,]    1    0    0    0    1
 [5,]    0    1    1    0    0
 [6,]    0    1    0    1    0
 [7,]    0    1    0    0    1
 [8,]    0    0    1    1    0
 [9,]    0    0    1    0    1
[10,]    0    0    0    1    1
[1] 1
     [,1] [,2] [,3] [,4] [,5]
[1,] 0.58 0.34 0.48 0.33 0.27
[1] 2
      [,1] [,2]
 [1,]   32   34
 [2,]   32   46
 [3,]   32   89
 [4,]   32   35
 [5,]   34   46
 [6,]   34   89
 [7,]   34   35
 [8,]   46   89
 [9,]   46   35
[10,]   89   35
 [1] 155.1724 151.0057 324.8694 184.8020 195.8333 369.6970 229.6296 365.5303
 [9] 225.4630 399.3266
   X1 X2 X3 X4 X5      Est    p
1   1  1  0  0  0 155.1724 0.13
2   1  0  1  0  0 151.0057 0.20
3   1  0  0  1  0 324.8694 0.15
4   1  0  0  0  1 184.8020 0.10
5   0  1  1  0  0 195.8333 0.15
6   0  1  0  1  0 369.6970 0.04
7   0  1  0  0  1 229.6296 0.02
8   0  0  1  1  0 365.5303 0.06
9   0  0  1  0  1 225.4630 0.07
10  0  0  0  1  1 399.3266 0.08
[1] 236
[1] 236
      [,1] [,2] [,3] [,4] [,5]
 [1,]    0    0    0    0    0
 [2,]    1    0    0    0    0
 [3,]    0    1    0    0    0
 [4,]    0    0    1    0    0
 [5,]    0    0    0    1    0
 [6,]    0    0    0    0    1
 [7,]    1    1    0    0    0
 [8,]    1    0    1    0    0
 [9,]    1    0    0    1    0
[10,]    1    0    0    0    1
[11,]    0    1    1    0    0
[12,]    0    1    0    1    0
[13,]    0    1    0    0    1
[14,]    0    0    1    1    0
[15,]    0    0    1    0    1
[16,]    0    0    0    1    1
[17,]    1    1    1    0    0
[18,]    1    1    0    1    0
[19,]    1    1    0    0    1
[20,]    1    0    1    1    0
[21,]    1    0    1    0    1
[22,]    1    0    0    1    1
[23,]    0    1    1    1    0
[24,]    0    1    1    0    1
[25,]    0    1    0    1    1
[26,]    0    0    1    1    1
[27,]    1    1    1    1    0
[28,]    1    1    1    0    1
[29,]    1    1    0    1    1
[30,]    1    0    1    1    1
[31,]    0    1    1    1    1
[32,]    1    1    1    1    1
[1] 1
     [,1] [,2] [,3] [,4] [,5]
[1,]  0.1  0.1  0.1  0.1  0.1
[1] 0.5
      [,1] [,2] [,3] [,4] [,5]
 [1,]   NA   NA   NA   NA   NA
 [2,]   32   NA   NA   NA   NA
 [3,]   34   NA   NA   NA   NA
 [4,]   46   NA   NA   NA   NA
 [5,]   89   NA   NA   NA   NA
 [6,]   35   NA   NA   NA   NA
 [7,]   32   34   NA   NA   NA
 [8,]   32   46   NA   NA   NA
 [9,]   32   89   NA   NA   NA
[10,]   32   35   NA   NA   NA
[11,]   34   46   NA   NA   NA
[12,]   34   89   NA   NA   NA
[13,]   34   35   NA   NA   NA
[14,]   46   89   NA   NA   NA
[15,]   46   35   NA   NA   NA
[16,]   89   35   NA   NA   NA
[17,]   32   34   46   NA   NA
[18,]   32   34   89   NA   NA
[19,]   32   34   35   NA   NA
[20,]   32   46   89   NA   NA
[21,]   32   46   35   NA   NA
[22,]   32   89   35   NA   NA
[23,]   34   46   89   NA   NA
[24,]   34   46   35   NA   NA
[25,]   34   89   35   NA   NA
[26,]   46   89   35   NA   NA
[27,]   32   34   46   89   NA
[28,]   32   34   46   35   NA
[29,]   32   34   89   35   NA
[30,]   32   46   89   35   NA
[31,]   34   46   89   35   NA
[32,]   32   34   46   89   35
 [1]    0  320  340  460  890  350  660  780 1210  670  800 1230  690 1350  810
[16] 1240 1120 1550 1010 1670 1130 1560 1690 1150 1580 1700 2010 1470 1900 2020
[31] 2040 2360
   X1 X2 X3 X4 X5  Est       p
1   0  0  0  0  0    0 0.59049
2   1  0  0  0  0  320 0.06561
3   0  1  0  0  0  340 0.06561
4   0  0  1  0  0  460 0.06561
5   0  0  0  1  0  890 0.06561
6   0  0  0  0  1  350 0.06561
7   1  1  0  0  0  660 0.00729
8   1  0  1  0  0  780 0.00729
9   1  0  0  1  0 1210 0.00729
10  1  0  0  0  1  670 0.00729
11  0  1  1  0  0  800 0.00729
12  0  1  0  1  0 1230 0.00729
13  0  1  0  0  1  690 0.00729
14  0  0  1  1  0 1350 0.00729
15  0  0  1  0  1  810 0.00729
16  0  0  0  1  1 1240 0.00729
17  1  1  1  0  0 1120 0.00081
18  1  1  0  1  0 1550 0.00081
19  1  1  0  0  1 1010 0.00081
20  1  0  1  1  0 1670 0.00081
21  1  0  1  0  1 1130 0.00081
22  1  0  0  1  1 1560 0.00081
23  0  1  1  1  0 1690 0.00081
24  0  1  1  0  1 1150 0.00081
25  0  1  0  1  1 1580 0.00081
26  0  0  1  1  1 1700 0.00081
27  1  1  1  1  0 2010 0.00009
28  1  1  1  0  1 1470 0.00009
29  1  1  0  1  1 1900 0.00009
30  1  0  1  1  1 2020 0.00009
31  0  1  1  1  1 2040 0.00009
32  1  1  1  1  1 2360 0.00001
[1] 236
[1] 236
 [1] 0.122500 0.157500 0.122500 0.087500 0.087500 0.050625 0.078750 0.056250
 [9] 0.056250 0.030625 0.043750 0.043750 0.015625 0.031250 0.015625
[1] 1
      [,1] [,2] [,3] [,4] [,5]
 [1,]    1    0    0    0    0
 [2,]    1    1    0    0    0
 [3,]    1    0    1    0    0
 [4,]    1    0    0    1    0
 [5,]    1    0    0    0    1
 [6,]    0    1    0    0    0
 [7,]    0    1    1    0    0
 [8,]    0    1    0    1    0
 [9,]    0    1    0    0    1
[10,]    0    0    1    0    0
[11,]    0    0    1    1    0
[12,]    0    0    1    0    1
[13,]    0    0    0    1    0
[14,]    0    0    0    1    1
[15,]    0    0    0    0    1
      [,1] [,2]
 [1,]   32   32
 [2,]   32   34
 [3,]   32   46
 [4,]   32   89
 [5,]   32   35
 [6,]   34   34
 [7,]   34   46
 [8,]   34   89
 [9,]   34   35
[10,]   46   46
[11,]   46   89
[12,]   46   35
[13,]   89   89
[14,]   89   35
[15,]   35   35
[1] 0.577500 0.399375 0.319375 0.234375 0.234375
 [1]  55.41126 140.54428 199.44257 435.14459 204.74459  85.13302 229.16433
 [8] 464.86635 234.46635 144.03131 523.76464 293.36464 379.73333 529.06667
[15] 149.33333
   X1 X2 X3 X4 X5       Est        p
1   1  0  0  0  0  55.41126 0.122500
2   1  1  0  0  0 140.54428 0.157500
3   1  0  1  0  0 199.44257 0.122500
4   1  0  0  1  0 435.14459 0.087500
5   1  0  0  0  1 204.74459 0.087500
6   0  1  0  0  0  85.13302 0.050625
7   0  1  1  0  0 229.16433 0.078750
8   0  1  0  1  0 464.86635 0.056250
9   0  1  0  0  1 234.46635 0.056250
10  0  0  1  0  0 144.03131 0.030625
11  0  0  1  1  0 523.76464 0.043750
12  0  0  1  0  1 293.36464 0.043750
13  0  0  0  1  0 379.73333 0.015625
14  0  0  0  1  1 529.06667 0.031250
15  0  0  0  0  1 149.33333 0.015625
[1] 236
[1] 236

TeachingSampling documentation built on April 22, 2020, 1:05 a.m.