3. (2 points) - Buservice Inc. performed a thorough review of the monthly maintenance cost for all 1-year-old buses subjected to the traditional preventive maintenance program and verified that the population of all 1-year-old buses had a mean monthly maintenance cost of $2,200 and standard deviation of =$450. What are the sampling distributions of for monthly maintenance costs for this population of 1-year-old buses for sample size of 10 and 20 buses? UPLOAD THE EXCEL SPREADSHEET FOR THIS CALCULATION IN ORDER TO GET POINTS FOR THIS TOPIC. 4. (5 points) - Buservice Inc. is a very customer focused organization and has a goal to provide the best service to their customers. Last month Buservice Inc. conducted a survey of 2,200 customers and asked if every customer is satisfied with the bus service provided. The survey revealed that 250 customers are not satisfied with the bus service. a. ( 0.5 points) - Calculate the point estimate for the proportion of customers () who are NOT satisfied with the bus service. b. (1 point) - Verify if the sampling distribution of can be approximated by a normal distribution. Show all steps of your calculations. 3. (2 points) - Buservice Inc. performed a thorough review of the monthly maintenance cost for all 1-year-old buses subjected to the traditional preventive maintenance program and verified that the population of all 1-year-old buses had a mean monthly maintenance cost of $2,200 and standard deviation of =$450. What are the sampling distributions of for monthly maintenance costs for this population of 1-year-old buses for sample size of 10 and 20 buses? UPLOAD THE EXCEL SPREADSHEET FOR THIS CALCULATION IN ORDER TO GET POINTS FOR THIS TOPIC. 4. (5 points) - Buservice Inc. is a very customer focused organization and has a goal to provide the best service to their customers. Last month Buservice Inc. conducted a survey of 2,200 customers and asked if every customer is satisfied with the bus service provided. The survey revealed that 250 customers are not satisfied with the bus service. a. ( 0.5 points) - Calculate the point estimate for the proportion of customers () who are NOT satisfied with the bus service. b. (1 point) - Verify if the sampling distribution of can be approximated by a normal distribution. Show all steps of your calculations