please show wll work

4. [20 Points! The time required for an automotive center to complete an oil change service on an automobile approximately follows a normal distribution, with a mean of 17 minutes and a standard deviation of 2 minutes. (a) The automotive center guarantees customers that the service will take no longer than 20 minutes. If it does take longer, the customer will receive the service for hall.price. What percent of customers receive the service for half-price? (b) If the automotive center does not want to give the discount to more than 2% of its customers, how long should it make the guaranteed time limit? 5. [10 Points Acconding to a study conducted by a statistical organization, the proportion of Americans who are satisfied with the way things are going in their lives is 0.8. Suppose that a random sample of 110 Americans is obtained. a. Describe the sampling distribution of sample proportion h. Using the distribution from part(s), what is the probability that at least 2 Americans in the comple are satisfied with their lives? 6. [20 Points) In a poll, 202 of 1010 randomly selected adults aged 18 or older stated that they believe there is too little spending on national defense. Use this information to complete parts (a) through (e) below a. Obtain a point estimate for the proportion of adults aged 18 or older who feel there is too little spending on national defense. Construct a 90% confidence interval for the proportion of adults aged 18 or older who believe there is too little spending on national defense