D Question 1 Which statements are true about Student t- distribution (select all that applies)? 0 We use t-distribution (instead of 2) when the population standard deviation is unknown 0 The graph of the density function is symmetric O The degrees of freedom is n Q We use t-distribution (instead of 2) when the population standard deviation is known D Question 3 2 pts A random sample of 40 ELAC students are surveyed about their commuting time. A mean of 24.5 minutes was calculated from the survey. The population standard deviation is known to be 5.8 minutes. Construct a 95% condence interval for the average commuting time for all ELAC students. Round your answer to the nearest tenth of a minute. Condence Interval: ( . 2pts D Question 2 2 pts A random sample of 40 ELAC students are surveyed about their commuting time. A mean of 24.5 minutes and a standard deviation of 5.8 minutes were calculated from the survey. Construct a 95% condence interval for the average commuting time for all ELAC students. Round your answer to the nearest tenth of a minute. Condence Interval: ( . D Question 4 1 pts When constructing a condence interval for the population mean, what would happen to the length of the condence interval when the sample mean gets larger (assuming everything else is unchanged)? 0 gets larger 0 gets smaller 0 not enough information is given 0 stay the same