Week 6 Assignment Confidence Interval For Mean Population Standard Deviation

QuestionSuppose scores of a standardized test are normally distributed and have a known population standard deviation of 11 points and an unknown population mean. A random sample of 15 scores is taken and gives a sample mean of 101 points. Find the confidence interval for the population mean with a 98% confidence level.z 0.10 z 0.05 z 0.025 z 0.01 z 0.0051.282 1.645 1.960 2.326 2.576You may use a calculator or the common z values above. Round the final answer to two decimal places.QuestionSuppose the weights, in pounds, of the dogs in a city are normally distributed. If the population standard deviation is 3 pounds, what minimum sample size is needed to be 95 % confident thatthe sample mean is within 1 pound of the true population mean?z 0.10 1.282 z 0.05 1.645 z 0.025 1.960 z 0.01 2.326 z 0.005 2.576Use the table above for the z -score, and be sure to round up to the nearest integer.QuestionSuppose the number of dollars spent per week on groceries is normally distributed. If the population standard deviation is 7 dollars, what minimum sample size is needed to be 90 % confident that the sample mean is within 3 dollars of the