1.8

  1. each raw of the data matrix represent a particpant or a case
  2. there 1691 particpants in the survey
  3. sex: categorical, nominal, age: numerical,discrete, marital: categorical, nominal grossIncome: categorical,ordinal, somke: categorical, nomina, amtWeekends: numerical,discrete amtWeekdays : numerical,discrete

1.10

  1. Population: all children, sample： 160 children between age 5 and 15
  2. if age between 5 to 15 can be consider to be resprentive to all children,then the result of study can be generalized to the population, however,since the study has no rendom assign,so is obversional, the study can not be used to established causal relationship

1.28

  1. since other factor had been adjusted, the study can not be used to established causal relationship
  2. the statement is not justfied, the result can be described as there is an association between sleep sidorder and bullying

1.36

  1. mental health
  2. treatment exercise twice a week, control group is no erercise
  3. not blocking since there are only one group in both treatment and control group
  4. no blinding since people know if they need to ererice or not

1.48

a <- c(57,66,69,71,72,73,74,77,78,79,81,81,82,83,83,88,89,94)
s<-summary(a) 
i<- summary(a)[5] - summary(a)[2] 
muwr <-s[5] + 1.5*i
mlwr <-s[2] - 1.5*i
paste('IQR is' ,i)
## [1] "IQR is 10.5"
paste('upper Whisker is' ,muwr)
## [1] "upper Whisker is 98.5"
paste('lower Whisker is' ,mlwr)
## [1] "lower Whisker is 56.5"
boxplot(a)

1.5

  1. Unimodal and symmetric (2)
  2. Uniform (3)
  3. Unimodal and right skewed (1)

1.56

  1. right skewed, IQR
  2. symmetric, stander deviation c)left skewed, IQR d)riht skewed, IQR

1.70

url <- "https://raw.githubusercontent.com/jbryer/DATA606Spring2017/master/Data/Data%20from%20openintro.org/Ch%201%20Exercise%20Data/heartTr.csv"
data <- read.csv(url,head=TRUE,sep = ',')
table(data$survived,data$transplant)
##        
##         control treatment
##   alive       4        24
##   dead       30        45
  1. no, becuase the proportion of survive in treatmeant group is much larger than control group
  2. it suggests that compare to no heart transplant, it’s effective however, the effect vearies for patient who live longner and it’s more stable to extend patient life for a short period
  3. 88.3% of patients in control group died and 65.2% of patients in treatment group died d)i the survivsl is indepentent of weather the patient get heart transplant or not d)ii 75,28, 69,34,0,less than -0.23, d)iii since none result is less than -0.23 it shows it’s effective