CI for proportion day 2

Which of the following is the critical value for a 86% confidence interval for a population proportion?

• 0.67

• 0.86

• 1.08

• 1.48

The management team of a company with 10,000 employees is considering installing charging stations for electric cars in the company parking lots. In a random sample of 500 employees, 15 reported owning an electric car. Which of the following is a 99 percent confidence interval for the proportion of all employees at the company who own an electric car?

• $0.03\pm2.326\sqrt{\frac{\left(0.03\right)\left(0.97\right)}{500}}$

• $0.15\pm2.326\sqrt{\frac{\left(0.15\right)\left(0.85\right)}{500}}$

• $0.03\pm2.576\sqrt{\frac{\left(0.03\right)\left(0.97\right)}{500}}$

• $0.15\pm2.576\sqrt{\frac{\left(0.15\right)\left(0.85\right)}{500}}$

A 98% confidence interval for the proportion of students who write/label their names on their computer stylus is

 $0.6\pm2.33\sqrt{\frac{\left(0.6\right)\left(0.4\right)}{300}}$ . Which part of this confidence interval is the STANDARD ERROR of the sample proportion?

• 0.6

• 2.33

•  $2.33\sqrt{\frac{\left(0.6\right)\left(0.4\right)}{300}}$  

•  $\sqrt{\frac{\left(0.6\right)\left(0.4\right)}{300}}$  

 $0.6\pm2.33\sqrt{\frac{\left(0.6\right)\left(0.4\right)}{300}}$  Which part of the confidence interval is the MARGIN OF ERROR?

• 0.6

• 2.33

•  $2.33\sqrt{\frac{\left(0.6\right)\left(0.4\right)}{300}}$  

•  $\sqrt{\frac{\left(0.6\right)\left(0.4\right)}{300}}$