Question

Find a 90% confidence interval for a population mean μ for these values. (Round your answers to three decimal places.)

a) n = 140, x = 0.87, s² = 0.084

b) n = 90, x = 29.1, s² = 3.66

A random sample of n = 500 observations from a binomial population produced x = 345 successes. Find a 90% confidence interval for p. (Round your answers to three decimal places.)

__ to __

Acid rain, caused by the reaction of certain air pollutants with rainwater, appears to be a growing problem in Eastern Canada. (Acid rain affects the soil and causes corrosion on exposed metal surfaces.) Pure rain falling through clean air registers a pH value of 5.7 (pH is a measure of acidity: 0 is acid; 14 is alkaline). Suppose water samples from 90 rainfalls are analyzed for pH, and xand s are equal to 3.9 and 0.7, respectively. Find a 99% confidence interval for the mean pH in rainfall. (Round your answers to three decimal places.)

__ to __

Answer 1

Problem 2

Problem 3