Aviation and high-altitude physiology is a specialty in the study of medicine. Letx= partial pressure of oxygen in the alveoli (air cells in the lungs) when breathing naturally available air. Lety= partial pressure when breathing pure oxygen. The (x, y) data pairs correspond to elevations from 10,000 feet to 30,000 feet in 5000 foot intervals for a random sample of volunteers. Although the medical data were collected using airplanes, they apply equally well to Mt. Everest climbers (summit 29,028 feet).

x	7.2	4.9	4.2	3.3	2.1	(units: mm Hg/10)
y	44.6	31.7	26.2	16.2	13.9	(units: mm Hg/10)

(a) Verify thatx=21.7,y=132.6,x²=108.79,y²=4136.14,xy=669.14, andr0.984.

x
y
x2
y2
xy
r

(b) Use a10%level of significance to test the claim that> 0. (Use 2 decimal places.)

t
criticalt

(c) Verify thatS_e2.5362,a-1.297, andb6.410.

Se
a
b

(d) Find the predicted pressure when breathing pure oxygen if the pressure from breathing available air isx=3.1. (Use 2 decimal places.) (e) Find a90%confidence interval forywhenx=3.1. (Use 1 decimal place.)

lower limit
upper limit

(f) Use a10%level of significance to test the claim that> 0. (Use 2 decimal places.)

t
criticalt

(g) Find a90%confidence interval forand interpret its meaning. (Use 2 decimal places.)

lower limit
upper limit