Task C, practical 9
Relationship between mean age of children in a family and height of Christmas tree was studied
Does the age of children in family affect the height of the Christmas tree bought by the parents?
Yunyun Tsai, Dragana  Vukić, Senka Baškiera

Result
 Null-hypothesis: the age of children in family does not affect the height of the Christmas tree
bought by the parents.

 tree<-read.delim("clipboard")
 summary(tree)

 plot(tree.height~age, data=tree)

Result
 cor.test(tree$tree.height, tree$age) We rejected the null-hypothesis.

 Pearson's product-moment correlation
 data:  tree$tree.height and tree$age
 t = -3.8541, df = 8, p-value = 0.004849
 alternative hypothesis: true correlation is not equal to 0
 95 percent confidence interval:
  -0.9523889 -0.3585995
 sample estimates:       cor -0.8061992