Suppose that insurance companies did a survey. They randomly surveyed 450 drivers and found that 320 ciaimed they alwarys buckle up. We are interested in the population proportion of drivers who claim they always buckle up. NOTE: If you are using a Student's twistribution, you may assume that the underlying population is normally distributed. (In general, you must first prove that assumption, though.) Part [a] Part (b) Part (c) Part (d) Construct a 95% confidence inserval for the population proportion who claint they always buckle up. (i) State the confidence interval. (Round your anseers to four decimal places.) (ii) Sketch the graph. 2=C== (iii) Calculate the ecror bound. (Round your answer to four decimal places.) x.