Question

An automotive manufacturer wants to know the proportion of new car buyers who prefer foreign cars over domestic.

Step 1 of 2:

Suppose a sample of 383 new car buyers is drawn. Of those sampled, 137 preferred foreign over domestic cars. Using the data, estimate the proportion of new car buyers who prefer foreign cars. Enter your answer as a fraction or a decimal number rounded to three decimal places.

Step 2 of 2:

Suppose a sample of 383 new car buyers is drawn. Of those sampled, 137 preferred foreign over domestic cars. Using the data, construct the 80% confidence interval for the population proportion of new car buyers who prefer foreign cars over domestic cars. Round your answers to three decimal places.

Answer 1

1) proportion estimate = 137 / 383 = 0.358

2) Z for 80% confidence interval = Z_0.1 = 1.28

Confidence interval

                               

                               

                                = (0.327 , 0.389)