From previous studies, it is concluded that 76% of car crashes occur within 2 miles of the motorists home.

Question

From previous studies, it is concluded that 76% of car crashes occur within 2 miles of the motorists home. A researcher claims it has increased and decides to survey 100 adults. Test the researcher's claim at the a=0.05 significance level. 

Express the null and alternative hypotheses in symbolic form for this claim. 

What is the p-value?

Verify np(1-p)>10



Answer 1

alpha = .05, one tailed test df =100-1 =99

use z distribution

Ho: mu = .76

H1: mu > .76

z critical comes from the z tables or a z calculator = about 1.645

calculate z observed = (x-xbar)/s/sqr99 where s= standard deviation of sample

if z obs > z critical, reject Ho

otherwise fail to retain Ho

x bar = np

var = np(1-p)=npq

s = sqrvar = sqrnpq