Question

a) In a recent poll, 130 people were asked if they liked dogs, and 25% said they did. Find the margin of error of this poll, at the 95% confidence level. Give your answer to three decimals. b) In a survey, 15 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $30 and standard deviation of $10. Find the margin of error at a 90% confidence level. Give your answer to two decimal places. c) You want to obtain a sample to estimate a population proportion. Based on previous evidence, you believe the population proportion is approximately p = 23%. You would like to be 98% confident that your estimate is within 1% of the true population proportion. How large of a sample size is required? n =

          a) In a recent poll, 130 people were asked if they liked dogs, and 25% said they did. Find the margin of error of this poll, at the 95% confidence level. Give your answer to three decimals.
b) In a survey, 15 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $30 and standard deviation of $10. Find the margin of error at a 90% confidence level. Give your answer to two decimal places.
c) You want to obtain a sample to estimate a population proportion. Based on previous evidence, you believe the population proportion is approximately p = 23%. You would like to be 98% confident that your estimate is within 1% of the true population proportion. How large of a sample size is required?
n =

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