You want to obtain a sample to estimate how much parents spend on their kids birthday parties. Based on previous study, you believe the population standard deviation is approximately σ=30.8σ=30.8 dollars. You would like to be 98% confident that your estimate is within 5 dollar(s) of average spending on the birthday parties. How many parents do you have to sample?
Added by Carol M.
Step 1
Given that we want to be 98% confident, we need to find the z-score that corresponds to a 98% confidence level. From the standard normal distribution table, the z-score for a 98% confidence level is approximately 2.33. Show more…
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