Insurance companies are interested in knowing the population percent of drivers who always buckle up before riding in a car. They randomly survey 420 drivers and find that 286 claim to always buckle up. Construct a 84% confidence interval for the population proportion that claim to always buckle up. Use interval notation, for example, [1,5]
Solution :
Given that,
Point estimate = sample proportion = = x / n = 286 / 420 = 0.681
1 - = 0.319
Z/2 = 1.405
Margin of error = E = Z / 2 * (( * (1 - )) / n)
= 1.405 * (((0.681 * 0.319) / 420)
= 0.032
A 84% confidence interval for population proportion p is ,
- E < p < + E
0.681 - 0.032 < p < 0.681 + 0.032
0.649 < p < 0.713
The 84% confidence interval for the population proportion p is : [0.649 , 0.713]
Get Answers For Free
Most questions answered within 1 hours.