library(readxl)
data_heart <- read_excel("a4_heart_disease_uci.xlsx")
View(data_heart)
age <- data_heart$age
n <- length(age)
x_barra <- mean(age)
mu_hat <- x_barra
s2_muestral <- var(age)
sigma2_hat <- s2_muestral
round(mu_hat, 2)
## [1] 53.51
round(sigma2_hat, 2)
## [1] 88.82
x_barra_formula <- sum(age)/n
s2_formula <- sum((age - x_barra)^2)/(n- 1)
x_barra_formula
## [1] 53.51087
s2_formula
## [1] 88.82469
s <- sqrt(s2_muestral)
sigma0 <- sqrt(36)
z <- qnorm(0.975)
LI_conocida <- x_barra- z * sigma0 / sqrt(n)
LS_conocida <- x_barra + z * sigma0 / sqrt(n)
round(c(LI_conocida, LS_conocida), 2)
## [1] 53.12 53.90
t <- qt(0.975, df = n- 1)
LI_desconocida <- x_barra- t * s / sqrt(n)
LS_desconocida <- x_barra + t * s / sqrt(n)
round(c(LI_desconocida, LS_desconocida), 2)
## [1] 52.90 54.12
mu0 <- 50
sigma <- 1
alpha <- 0.05
x_bar <- 53.51
z <- (x_bar- mu0) / (sigma / sqrt(n))
z_critico <- qnorm(1- alpha)
if (z > z_critico) { decision <- "Rechazamos H0" } else { decision <- "No rechazamos H0" }
p_valor <- 1- pnorm(z)