A random sample of the number of farms (in thousands) in various states follows.

Question

A random sample of the number of farms (in thousands) in various states follows. Estimate the mean number of farms per state with 90% confidence. Assume sigma = 31.0. Television Viewing A study of 415 randomly selected kindergarten students showed that they have seen on average 5000 hours of television. If the sample standard deviation of the population is 900, find the 95% confidence interval of the mean for all students. If a father claimed that his children watched 4000 hours, would the claim be believable? Day Care Tuition A random sample of 50 four-year-olds attending day care centers provided a yearly tuition average of $3987 and the population standard deviation of $630. Find the 90% confidence interval of the true mean. If a day care center were starting up and wanted to keep tuition low, what would be a reasonable amount to charge?

Explanation / Answer

Solving question 16 which is the first question as per Chegg policy.

Mean(x_bar) = Sum (47+95+....40+50+29) / 31 = 43.45

Standard deviation = 31

z for 90% interval is 1.645

Confidence interval =  [x_bar - z*s/sqrt(n) ,x_bar + z*s/sqrt(n)]

=[43.45 - 1.645*31/sqrt(31), 43.45 + 1.645*31/sqrt(31)] = (34.29,52.60)

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