Question

the number of domestic flights in the United States over several years. To save typing, I have enclosed only the data from 2008 to 2015.

(a) Make a scatterplot of the data using Year as the explanatory variable and Flights as the response variable.

(b)   Discuss the direction, form, and strength of the relationship.

(c)   Compute the correlation coefficient.

(d)   Does this prove that the number of U.S. domestic flights is decreasing as time passes?? Why or why not?

Year      2008            2009         2010            2011            2012          2013              2014         2015

Flight   9378227     8768938    8702365     8649087   8446200    8323938    8107802      8061158

Answer 1

I used R software to solve this question.

R codes and output:

year=seq(2008,2015);year

[1] 2008 2009 2010 2011 2012 2013 2014 2015
flight=c(9378227,8768938,8702365,8649087,8446200,8323938,8107802,8061158)
plot(year,flight,main='Scatter plot')
cor(year,flight)

[1] -0.9516743

Que. a

Que.b

Here we see that as year increases, number of flight decreases. It means there is negative correlation between number of flights and years.

Except one point, all the points are lie in a straight line. Hence it is high degree negative correlation.

Que.c

Correlation =  -0.9516743

Que.d

Yes, it proves that the number of U.S. domestic flights is decreasing as time passes , because value of correlation coefficient is negative and very (high) close to -1.