Question

Given that 58% of people don’t drink enough water in a day, in a SRS of 150 people what is the probability that between 55% and 60% of the sample don’t drink enough water?

0.05

0.12

0.31

0.46

Answer 1

Sol:

mean=p=0.58

sample size=n=150

sample standard deviation,=sqrt(p*(1-p)/n)=sqrt(0.58*(1-0.58)/150)= 0.04029888

sample follows normal d

P(0.55<p^<0.60)

Using R code:

library(tigerstats)
pnormGC(bound=c(0.55,0.60),region="between", mean=0.58,sd=0.04029888,graph=TRUE)

0.46