Question

Pure-bred dogs competing in shows must often meet specific height criteria to be considered to be within the breed standard. A new breed of dog, the pug-cock-a-poo, has been approved by a kennel club. The standard deviation of pug-cock-a-poo height is known to be 1.92 inches squared. You would like to estimate the mean height of all pug-cock-a-poo breeds of dogs. Find the appropriate sample size to achieve a margin of error of 0.02 when maintaining a 90% level of confidence.

(no excel work)

Answer 1

Solution :

Given that,

Population standard deviation = = 1.92

Margin of error = E = 0.02

At 90% confidence level

= 1-0.90% =1-0.90 =0.10

/2 =0.10/ 2= 0.05

Z/2 = Z0.05 = 1.645

Z/2 = 1.645  

sample size = n = [Z/2* / E] 2

n = [ 1.645 * 1.92 / 0.02 ]2

n = 24939

Sample size = n = 24939