Basic Example

Mónica Isabel Blanco 2025-11-13

library(ggplot2)
library(dplyr)
## 
## Attaching package: 'dplyr'

## The following objects are masked from 'package:stats':
## 
##     filter, lag

## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union
summary(quakes)
##       lat              long           depth            mag      
##  Min.   :-38.59   Min.   :165.7   Min.   : 40.0   Min.   :4.00  
##  1st Qu.:-23.47   1st Qu.:179.6   1st Qu.: 99.0   1st Qu.:4.30  
##  Median :-20.30   Median :181.4   Median :247.0   Median :4.60  
##  Mean   :-20.64   Mean   :179.5   Mean   :311.4   Mean   :4.62  
##  3rd Qu.:-17.64   3rd Qu.:183.2   3rd Qu.:543.0   3rd Qu.:4.90  
##  Max.   :-10.72   Max.   :188.1   Max.   :680.0   Max.   :6.40  
##     stations     
##  Min.   : 10.00  
##  1st Qu.: 18.00  
##  Median : 27.00  
##  Mean   : 33.42  
##  3rd Qu.: 42.00  
##  Max.   :132.00
poblacion <- quakes
N_poblacion <- nrow(poblacion)
media_poblacional <- mean(poblacion$mag)
desviacion_poblacional <- sd(poblacion$mag)

cat("Tamaño de la Población (N):", N_poblacion, "\n")
## Tamaño de la Población (N): 1000
cat("Media Poblacional de Magnitud (mu):", round(media_poblacional, 3), "\n")
## Media Poblacional de Magnitud (mu): 4.62
cat("Desviación Estándar Poblacional (sigma):", round(desviacion_poblacional, 3), "\n")
## Desviación Estándar Poblacional (sigma): 0.403

#Muestra

set.seed(123)
n_muestra <- 150
muestra <- sample_n(poblacion, size = n_muestra, replace = FALSE)
muestra
##        lat   long depth mag stations
## 1   -21.50 185.20   139 4.4       15
## 2   -18.08 180.70   628 5.2       72
## 3   -17.84 181.48   542 4.1       20
## 4   -21.31 180.84   586 4.5       17
## 5   -32.20 179.61   422 4.6       41
## 6   -22.41 183.99   128 5.2       72
## 7   -16.21 186.52   111 4.8       30
## 8   -13.47 172.29    64 4.7       14
## 9   -30.64 181.20   175 4.0       16
## 10  -23.73 182.53   232 5.0       55
## 11  -18.20 183.68   107 4.8       52
## 12  -21.00 181.66   600 4.4       10
## 13  -19.77 181.40   630 5.1       54
## 14  -18.44 181.04   624 4.2       21
## 15  -28.10 182.25    68 4.6       18
## 16  -21.24 180.81   605 4.6       34
## 17  -19.85 184.51   184 4.4       26
## 18  -21.56 183.23   271 4.4       36
## 19  -15.48 167.53   128 5.1       61
## 20  -18.68 184.50   174 4.5       34
## 21  -27.38 182.39    69 4.5       12
## 22  -37.03 177.52   153 5.6       87
## 23  -27.27 182.36    65 4.7       21
## 24  -18.97 169.44   242 5.0       41
## 25  -17.94 181.49   537 4.0       15
## 26  -19.50 186.90    58 4.4       20
## 27  -33.00 182.40   176 4.6       28
## 28  -18.83 182.26   575 4.3       11
## 29  -12.27 167.41    50 4.5       29
## 30  -30.66 180.13   411 4.7       42
## 31  -23.47 180.21   553 4.2       23
## 32  -23.31 179.27   566 5.1       49
## 33  -13.62 167.15   209 4.7       30
## 34  -23.44 184.60    63 4.8       27
## 35  -20.91 181.57   530 4.2       20
## 36  -17.59 181.09   536 5.1       61
## 37  -21.60 169.90    43 5.2       56
## 38  -13.23 167.10   220 5.0       46
## 39  -16.20 166.80    98 4.5       21
## 40  -13.84 170.62   638 4.6       20
## 41  -33.29 181.30    60 4.7       33
## 42  -21.60 180.50   595 4.0       22
## 43  -17.46 181.42   524 4.2       16
## 44  -18.14 181.71   574 4.0       20
## 45  -15.80 185.25    82 4.4       39
## 46  -23.30 180.16   512 4.4       18
## 47  -17.98 181.61   598 4.3       27
## 48  -21.38 181.39   501 4.6       36
## 49  -21.30 180.82   624 4.3       14
## 50  -24.97 179.54   505 4.9       50
## 51  -23.47 179.95   543 4.1       21
## 52  -20.37 182.10   397 4.2       22
## 53  -34.20 179.43    40 5.0       37
## 54  -26.67 182.40   186 4.2       17
## 55  -20.60 182.28   529 5.0       50
## 56  -15.90 167.16    41 4.8       42
## 57  -19.86 184.35   201 4.5       30
## 58  -24.96 179.87   480 4.4       25
## 59  -18.18 182.04   609 4.4       26
## 60  -12.66 169.46   658 4.6       43
## 61  -17.91 181.48   555 4.0       17
## 62  -12.01 166.66    99 4.8       36
## 63  -30.01 181.15   210 4.3       17
## 64  -23.83 182.56   229 4.3       24
## 65  -25.31 179.69   507 4.6       35
## 66  -23.33 180.18   528 5.0       59
## 67  -17.40 187.80    40 4.5       14
## 68  -37.37 176.78   263 4.7       34
## 69  -18.40 183.40   343 4.1       10
## 70  -15.41 186.44    69 4.3       42
## 71  -17.40 181.02   479 4.4       14
## 72  -22.43 184.48    65 4.9       48
## 73  -13.26 167.01   213 5.1       70
## 74  -26.13 178.31   609 4.2       25
## 75  -32.82 179.80   176 4.7       26
## 76  -21.63 180.77   592 4.3       21
## 77  -30.51 181.30   203 4.4       20
## 78  -15.03 167.32   136 4.6       20
## 79  -17.02 182.93   406 4.0       17
## 80  -18.78 186.72    68 4.8       48
## 81  -17.66 181.40   585 4.1       17
## 82  -20.90 169.84    93 4.9       31
## 83  -21.29 185.77    57 5.3       69
## 84  -30.28 180.62   350 4.7       32
## 85  -22.70 170.30    69 4.8       27
## 86  -17.95 181.37   642 4.0       17
## 87  -23.55 180.80   349 4.0       10
## 88  -15.17 187.20    50 4.7       28
## 89  -18.54 182.11   554 4.4       19
## 90  -20.42 181.86   530 4.5       27
## 91  -17.74 181.25   559 4.1       16
## 92  -24.41 180.03   500 4.5       34
## 93  -23.61 180.23   475 4.4       26
## 94  -22.00 180.53   583 4.9       20
## 95  -24.78 179.22   492 4.3       16
## 96  -15.43 186.30   123 4.2       16
## 97  -17.70 181.31   549 4.7       33
## 98  -18.48 181.49   641 5.0       49
## 99  -22.10 179.71   579 5.1       58
## 100 -18.10 181.63   592 4.4       28
## 101 -24.40 179.85   522 4.7       29
## 102 -17.80 181.32   539 4.1       12
## 103 -14.65 166.97    82 4.8       28
## 104 -36.95 177.81   146 5.0       35
## 105 -24.81 180.00   452 4.3       19
## 106 -11.49 166.22    84 4.6       32
## 107 -22.70 183.30   180 4.0       13
## 108 -37.93 177.47    65 5.4       65
## 109 -19.60 185.20   125 4.4       13
## 110 -15.45 186.73    83 4.7       37
## 111 -20.14 181.60   587 4.1       13
## 112 -18.14 180.87   624 5.5      105
## 113 -25.63 180.26   464 4.8       60
## 114 -17.70 181.70   450 4.0       11
## 115 -35.48 179.90    59 4.8       35
## 116 -15.48 186.73    82 4.4       17
## 117 -18.75 182.35   554 4.2       13
## 118 -23.74 179.99   506 5.2       75
## 119 -17.42 185.16   206 4.5       22
## 120 -16.90 185.72   135 4.0       22
## 121 -23.54 179.93   574 4.0       12
## 122 -33.03 180.20   186 4.6       27
## 123 -11.41 166.24    83 5.3       55
## 124 -18.76 169.71   287 4.4       23
## 125 -19.30 183.84   517 4.2       21
## 126 -16.17 184.10   338 4.3       13
## 127 -18.69 169.10   218 4.2       27
## 128 -15.00 184.62    40 5.1       54
## 129 -23.73 183.00   118 4.3       11
## 130 -32.62 181.50    55 4.8       26
## 131 -38.59 175.70   162 4.7       36
## 132 -14.70 166.00    48 5.3       16
## 133 -21.40 180.78   615 4.7       51
## 134 -21.35 170.04    56 5.0       22
## 135 -26.00 178.43   644 4.9       27
## 136 -19.06 182.45   477 4.0       16
## 137 -18.07 181.54   546 4.3       28
## 138 -13.80 166.53    42 5.5       70
## 139 -23.34 184.50    56 5.7      106
## 140 -18.21 180.87   631 5.2       69
## 141 -19.60 181.87   597 4.2       18
## 142 -19.10 184.52   230 4.1       16
## 143 -11.34 166.24   103 4.6       30
## 144 -20.36 186.16   102 4.3       21
## 145 -15.54 167.68   140 4.7       16
## 146 -18.56 169.05   217 4.9       35
## 147 -20.42 181.96   649 4.0       11
## 148 -26.10 182.30    49 4.4       11
## 149 -20.40 186.10    74 4.3       22
## 150 -19.13 182.51   579 5.2       56
media_muestral<- mean(muestra$mag); media_muestral
## [1] 4.58
SE_media <- desviacion_poblacional / sqrt(n_muestra); SE_media
## [1] 0.03288628
Z_valor <- qnorm(0.95) 
margen_error <- Z_valor * SE_media
# limites de intervalo
limite_inf<- media_muestral - margen_error
limite_sup <- media_muestral + margen_error

cat("Valor Z (90%):", round(Z_valor, 3), "\n")
## Valor Z (90%): 1.645
cat("Margen de Error:", round(margen_error, 4), "\n")
## Margen de Error: 0.0541
cat("Intervalo de Confianza (90%) para la media de magnitud:", 
    round(limite_inf, 3), " a ", round(limite_sup, 3), "\n")
## Intervalo de Confianza (90%) para la media de magnitud: 4.526  a  4.634

#Proporcion

P_poblacional <- poblacion %>%
  mutate(grave = ifelse(mag >= 5.0, 1, 0)) %>%
  summarise(P = mean(grave)) %>%
  pull(P)

cat("Proporción Poblacional de Sismos Graves (P):", round(P_poblacional, 4), "\n")
## Proporción Poblacional de Sismos Graves (P): 0.198
p_muestral <- muestra %>%
  mutate(grave = ifelse(mag >= 5.0, 1, 0)) %>%
  summarise(p = mean(grave)) %>%
  pull(p)

cat("Proporción Muestral de Sismos Graves (p):", round(p_muestral, 4), "\n")
## Proporción Muestral de Sismos Graves (p): 0.2
SE_proporcion <- sqrt( (P_poblacional * (1 - P_poblacional)) / n_muestra )

cat("Error Estándar de la Proporción Muestral (SE_p):", round(SE_proporcion, 4), "\n")
## Error Estándar de la Proporción Muestral (SE_p): 0.0325