Question

1) After years of rapid growth, illegal immigration into the United States has declined, perhaps owing to the recession and increased border enforcement by the United States (Los Angeles Times, September 1, 2010). While its share has declined, California still accounts for 31% of the nation’s estimated 10.8 million undocumented immigrants. [You may find it useful to reference the z table.]

1a) In a sample of 40 illegal immigrants, what is the probability that more than 30% live in California? (Round “z” value to 2 decimal places, and final answer to 4 decimal places.)

1b) In a sample of 280 illegal immigrants, what is the probability that more than 30% live in California? (Round “z” value to 2 decimal places, and final answer to 4 decimal places.) c. Comment on the reason for the difference between the computed probabilities in parts a and b. As the sample number increases, the probability of more than 30% also increases, due to the lower z value and decreased standard error. As the sample number increases, the probability of more than 30% also increases, due to the lower z value and increased standard error.

2) A simple random sample of 14 observations is derived from a normally distributed population with a known standard deviation of 2.4. [You may find it useful to reference the z table.]

2a) Compute the margin of error with 99% confidence. (Round intermediate calculations to at least 4 decimal places. Round "z" value to 3 decimal places and final answer to 2 decimal places.)


2b.) Compute the margin of error with 95% confidence. (Round intermediate calculations to at least 4 decimal places. Round "z" value to 3 decimal places and final answer to 2 decimal places.)

Answer 1