Question

Domestic cats kill many more wild bird in the United States than scientist thought. Researchers used a sample of n=140 household in the US with cost to estimate that 35% of household cats in the US hunt outdoors.

Milius, S.,"Cats killed more than one billion birds each year, " Science News, 183(4), February 23, 2013, revised March 8, 2014. Date approximated from information give the article.

(a) Find a 90% confidence interval for the proportion of household cats in the US that hunt outdoors.

Round your answers to the three decimal places.

Th 90% confidence interval is _______ to ________.

Answer 1

In a sample of n = 140, 35% of household cats in the US hunt outdoors.

The sample proportion , = 0.35

z-value for 90% confidence interval = 1.645

The confidence interval is = z * (1-)/n

= 0.35 0.066

= (0.284 , 0.416)

The 90% confidence interval is 0.284 to 0.416.