Introduction to Biostatistics (BIOS 376, Section 001)
Homework 9 (25 pts)
Due. April 15
Makenna Mercer
Readings:
Textbook section 9.1.
1.
(4 pts) Look at the following diagrams. Which show high linear correlation, moderate or
low linear correlation, or no linear correlation?
a.
Moderate linear correlation
b.
No linear correlation
c.
High linear correlation
2.
(6pts) Describe the relationship between two variables when the correlation coefficient r
is
(a)
near -1.
There is a strong negative linear correlation.
(b) near 0.
There would be a weak correlation or no relationship.
(c)
near 1.
There is a strong positive linear correlation.
3.
(10 pts) Can a low barometer reading be used to predict maximum wind speed of an
approaching tropical cyclone? Data for this problem are based on information taken from
Weatherwise (Vol. 46, No. 1), a publication of the American Meteorological Society. For
a random sample of tropical cyclones, let x be the lowest pressure (in millibars) as a
cyclone approaches, and let y be the maximum wind speed (in miles per hour) of the
cyclone.
(a)
Make a scatter diagram and draw the line you think best fits the data using. Below are the
codes you might need.
x=c(1004, 975, 992, 935, 985, 932)
y=c(40, 100, 65, 145, 80, 150)
plot(x, y)
