A random sample of shoppers at a convenience store are selected to see how much they spent on that visit. The standard deviation of the population is $6.43. How large a sample must be selected if the researcher wants to be 99% confident of finding whether the true mean differs from the sample mean by $1.50?
Answer to relevant QuestionsIn the hospital study cited in Exercise 19, the mean noise level in the 171 ward areas was 58.0 decibels, and the population standard deviation is 4.8. Find the 90% confidence interval of the true mean. A random sample of stock prices per share (in dollars) is shown. Find the 90% confidence interval for the variance and standard deviation for the prices. Assume the variable is normally distributed. A study of generation related carbon monoxide deaths showed that a sample of 6 recent years had a standard deviation of 4.1 deaths per year. Find the 99% confidence interval of the variance and standard distribution. Assume ...In a Gallup Poll of 1005 individuals, 452 thought they were worse off financially than a year ago. Find the 95% confidence interval for the true proportion of individuals who feel they are worse off financially. If a sample of 600 people is selected and the researcher decides to have a margin of error of 4% on the specific proportion who favor gun control, find the degree of confidence. A recent study showed that 50% were in favor ...
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