Question

For each of the following data sets, construct a normal plot, and decide if the data
appear to be approximately normally distributed.
(a) 35, 43, 46, 51, 55, 58, 65.
(b) 2.0, 3.0, 3.2, 3.5, 3.7, 3.9, 4.0, 4.2, 4.4, 4.4, 4.5, 4.8, 5.0, 5.1, 5.4, 5.8, 6.1.

Answer 1

As most of points fall on the line so data appear to be normally distributed.

(b)

Same as in part a. every point except first one which is outliar falls on line so data appear to be normaly distributed.

we used the following r-code to draw the plot.

x=c(35, 43, 46, 51, 55, 58, 65)
y=c( 2.0, 3.0, 3.2, 3.5, 3.7, 3.9, 4.0, 4.2, 4.4, 4.4, 4.5, 4.8, 5.0, 5.1, 5.4, 5.8, 6.1)
qqnorm(x,main='Normal QQ plot for part a')
qqline(x)

qqnorm(y,main='Normal QQ plot for part b')
qqline(y)