Question

How much should a healthy Shetland pony weigh? Let x be the age of the pony (in months), and let y be the average weight of the pony (in kilograms).

x	3	6	12	15	26
y	60	95	140	150	177

$\sum$ x=62 $\sum$ x²=1090 $\sum \!$ y=622   $\sum \!$ y²=86,054 $\sum \!$ xy=9,282

a) Compute r. (Round your answer to three decimal places.)

Answer 1

r = [n $\sum$ XY - ( $\sum$ X * $\sum$ Y) ] / [ Sqrt( { n $\sum$ X² - ( $\sum$ X)² } {n $\sum$ Y² - ( $\sum$ Y)² } ]

= [ 5 * 9282 - 62 * 622 ] / [ Sqrt( 5 * 1090 - 62² ) ( 5 * 86054 - 622² ) ]

= [ 7846 ] / [ Sqrt( 1606 * 43386) ]

= 0.93994

r = 0.940 (Rounded to three decimal places)