Why is a sample proportion generally used to estimate a population proportion instead of obtaining the population proportion directly?

You want to obtain a sample to estimate a population proportion. Based on previous evidence, you believe the population proportion is approximately 10%. You would like to be 95% confident that your estimate is within 3% of the true population proportion. How large of a sample size is required? Do not round mid-calculation.

You want to obtain a sample to estimate a population proportion. Based on previous evidence, you believe the population proportion is approximately 40%. You would like to be 99% confident that your estimate is within 4.5% of the true population proportion. How large of a sample size is required?

You want to obtain a sample to estimate a population proportion. Based on previous evidence, you believe the population proportion is approximately 69%. You would like to be 99% confident that your estimate is within 4.5% of the true population proportion. How large of a sample size is required?

You want to obtain a sample to estimate a population proportion. Based on previous evidence, you believe the population proportion is approximately 12%. You would like to be 90% confident that your estimate is within 4.5% of the true population proportion. How large of a sample size is required?

True or False: p is the population proportion Select one: True False

You want to obtain a sample to estimate a population proportion. Based on previous evidence, you believe the population proportion is approximately 68%. You would like to be 95% confident that your estimate is within 3.5% of the true population proportion. How large of a sample size is required? Do not round mid-calculation.

A researcher wants to determine the percentage of American teenagers who send or receive text messages while doing homework. Which of the following techniques would likely be the MOST efficient way of obtaining an accurate estimate for this percentage? 1. Randomly select teenagers from the list of all teenage students in every state in America and mail surveys to those teens, asking them if they send or receive text messages while doing homework. 2. Send a survey to every teenager in America and ask them if they send or receive text messages while doing homework. 3. Randomly select teenagers from the list of all teenage students in one state and mail surveys to those teens, asking them if they send or receive text messages while doing homework.

You want to obtain a sample to estimate a population proportion. At this point in time, you have no reasonable estimate for the population proportion. You would like to be 99.5% confident that you esimate is within 1.5% of the true population proportion. How large of a sample size is required?

You want to obtain a sample to estimate a population proportion. Based on previous evidence, you believe the population proportion is approximately p∗=22%p∗=22%. You would like to be 95% confident that your esimate is within 4% of the true population proportion. How large of sample size is required?