The Police Department is Investigating the need for a speed camera to he Implemented on Hasty Road. A sample of 51 cars passing through that road on a particular day were randomly selected and their speeds recorded. The speed limit on Hasty Road ls El] miles per hour {mph}. The mean speed for the sample was calculated as 43 mph. The standard deviation of the speeds for the sample was calculated as 3 mph. 11-ie standard deviation for the population of cars driving on Hasty Road ls unknown. a} Select all the techniques that are commonly used to construct a oonfidenoe Interval for the mean when the population standard deviation Io} ls unknown: Approximate the population standard deviation {o} with the sample standard deviation [s] Ci Replace the sample size In] with n-1 Approximate the standard normal distribution with the Student's t distribution Cl Decrease the confidence level to compensate for the increased margin of error h} Calculate the upper and lower bounds of the 95% confidence interval for the mean speed traveled on Hasty Road. Give your answers In mph to 2 decimal places. Upper hound = mph Lower hound = mph