Bob Nale is the owner of Nale's Texaco GasTown. Bob would like to estimate the mean number of litres (L) of gasoline sold to his customers. Assume the number of litres sold follows the normal distribution with a standard deviation of 36 L. From his records, he selects a random sample of 27 sales and finds the mean number of litres sold is 83. a. What is the point estimate of the population mean? (Round the final answer to the nearest whole number.) The point estimate of the population mean is litres. b. Develop a 90% confidence interval for the population mean. (Round the final answers to 3 decimal places.) The 90% confidence interval for the population mean is between and c. Interpret the meaning of part (b). If 100 such intervals were determined, the population (Click to select) | would be included in about intervals.A sample of 24 observations is selected from a normal population for which the population standard deviation is known to be 10. The sample mean is 29. a. Determine the standard error of the mean. (Round the final answer to 3 decimal places.) The standard error of the mean is b. Explain why we can use formula (8-1) to determine the 98% confidence interval, even though the sample size is less than 30. (Click to select) The population is normally distributed and the population variance is unknown. The population is normally distributed and the population variance is known. d the intermediate calculation to 3 decimal places. Round The population is normally distributed and the sample variance is known. The 98% confidence interval for the population mean is between andA sample of 24 observations is selected from a normal population for which the population standard deviation is known to be 10. The sample mean is 29. a. Determine the standard error of the mean. (Round the final answer to 3 decimal places.) The standard error of the mean is b. Explain why we can use formula (8-1) to determine the 98% confidence interval, even though the sample size is less than 30. (Click to select) c. Determine the 98% confidence interval for the population mean. (Round the intermediate calculation to 3 decimal places. Round the final answers to 3 decimal places.) The 98% confidence interval for the population mean is between and