F I L E L ife e x p e c ta n c y a t b ir th is th e a v e ra g e n u m b e r o f ye ars th a t a p e rs o n is e x p e c te d to live . T h e re is a h u g e v a ria tio n in life e x p e c ta n c ie s b e tw e e n c o u n trie s w it h th e h ig h e s t b e in g in J a p a n , a n d th e lo w e s t in s o m e A fric a n c o u n trie s .

A n im p o r ta n t fa c to r fo r s u ch v a r ia b ility is th e a v a ila b ility o f s u ita b le h e a lth care. O n e m e a s u re o f a p ers o n 's access to h e a lth ca re is th e p e o p le -to -p h y s ic ia n ra tio . W e e x p e c t life e x p e c ta n c y to b e lo w e r fo r c o u n trie s w h e re th is ra tio is h ig h .

T h e a c c o m p a n y in g ta b le lists a p o r tio n o f life e x p e c ta n c y o f m a le s a n d fe m a le s in 4 0 c o u n trie s a n d th e ir c o rre s p o n d in g p e o p le -to -p h y s ic ia n ra tio ; th e c o m p le te d a ta , la b e le d Life Expectancy, a re a v a ila b le o n th e te x t w e b s ite .

Country Male Life Expectancy Female Life Expectancy People/

Physician Argentina 67 74 370 Bangladesh 54 53 6,166 Zaire 52 56 23,193 SOURCE: T he W o rld A lm a n a c a n d B o o k Fa c ts , 1 9 9 3 .

a. C o n s tru c t a s c a tte r p lo t o f fe m a le life e x p e c ta n c y a g a in s t th e p e o p le -to -p h y s ic ia n ra tio . S u p e rim p o s e a lin e a r tre n d a n d a lo g a r ith m ic tr e n d to d e te rm in e th e a p p ro p ria te m o d e l.

b. E s tim a te a s im p le lin e a r re g re s s io n m o d e l w it h life e x p e c ta n c y o f fe m a le s as th e re s p o n s e v a r ia b le a n d th e p e o p le -to -p h y s ic ia n r a tio as th e e x p la n a to ry v a ria b le .

W h a t h a p p e n s t o life e x p e c ta n c y o f fe m a le s as th e p e o p le - to - p h y s ic ia n r a tio d e c re a s e s fr o m 1 ,0 0 0 to 500?

c. E stim a te a lo g a rith m ic re g re ssio n m o d e l w ith th e n a tu ra l lo g o f th e p e o p le -to -p h y s ic ia n ra tio as th e e x p la n a to ry v a ria b le . W h a t h a p p e n s to life e x p e c ta n c y o f fe m a le s as th e p e o p le -to -p h y s ic ia n ra tio decreases fro m 1,000 to 500?

d. Use R2 to d e te rm in e w h ic h o f th e a b o v e tw o m o d e ls is m o re a p p ro p ria te .