classes/11feb_practica1.R

# == GENERACIÓ VARIABLES ALEATÒRIES ==
n = 100

# Nid
nid = sample(100:999, n, replace=F)

# Gènere
genere = sample(c("H", "D"), n, replace=T, prob=c(38, 62))
tg = table(genere)
tg
barplot(tg)

# Edat
edat_weights = c(5, 4, 2, 2, 1, 1)
edat = sample(19:24, n, replace=T, prob=edat_weights)
te = table(edat)
te_teoric = edat_weights*100/sum(edat_weights)

rbind(te, te_teoric)

plot(table(edat), ty="h")
points(19:24 + 0.1, te_teoric, ty="h", col="red")

# Pes
gamma_shape = 300
gamma_scale = 0.2
pes = rgamma(n, shape=gamma_shape, scale=gamma_scale)

mean(pes)
mithteorica = gamma_shape*gamma_scale
mithteorica

hist(pes, freq=F)
curve(dgamma(x, shape=gamma_shape, scale=gamma_scale), add=T)
curve(dgamma(x, shape=310, scale=0.22), col="red", add=T)

plot(sort(pes), (1:n)/n, ty="s")
curve(pgamma(x, shape=gamma_shape, scale=gamma_scale), add=T)
curve(pgamma(x, shape=301, scale=gamma_scale), add=T)

# Alçada
alçada = rnorm(n, 170, 8)

# Coneixement anglès
con_angles = sample(c("Cap", "Baix", "Mitjà", "Alt", "Molt Alt"), n, replace=T, prob=c(2, 7, 40, 30, 21))
# - Sense especificar l'ordre de les barres:
barplot(table(con_angles))
# - Especificant un ordre específic de les barres:
barplot(table(con_angles)[c("Cap", "Baix", "Mitjà", "Alt", "Molt Alt")])

# Nombre de germans
binom_prob = .3
binom_size = .5
ngermans = rnbinom(n, binom_size, binom_prob)
ngermans

table(ngermans)
plot(table(ngermans))
points(0:9 + 0.1, 100*dnbinom(0:9, binom_prob, binom_size), ty="h", col="red")

# == DATA FRAME ==
dd = data.frame(nid, genere, edat, pes, alçada, con_angles, ngermans)
head(dd)
write.csv2(dd, 'practica1.csv')