Question

In 1980 more than 35% of cars purchased had a manual transmission (ie, stick shift). By 2007 the proportion had decreased to 7.7%. A random sample of college students who owned cars revealed the following: out of 130 cars, 20 had stick shifts. Estimate the proportion of college students who drive sticks with 95% confidence. Round your answers to three decimal places. Source: www.pollingreport.com

Answer 1

Ans:

Sample proportion=20/130=0.154

95% confidence interval for p

=0.154+/-1.96*sqrt(0.154*(1-0.154)/130)

=0.154+/-0.062

=(0.092, 0.216)