D Question 2 2 pts Which of the following are requirements for using a condence interval to estimate the mean using a z-score? 0 Which of the following are requirements for using a condence interval to estimate the mean using a z-score? 0 population standard deviation is given 0 alpha is 0.05 0 population is normally distributed or n is large 0 np is greater than or equal to 5 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 size gets larger (assuming everything else is unchanged)? 0 stay the same 0 O 0 gets smaller 0 not enough information is given 0 gets larger D Question 5 D Question 3 2 pts A researcher surveyed 45 ELAC students and found that on average, students sleep 6.7 hours a night. A population standard deviation is known to be 0.7 hours. Construct the 95% condence interval for the average sleeping hour for all ELAC students. Round your answer to the nearest tenth of an hour. Condence interval: ( . 2pts The population standard deviation for the age of ELAC students is 13 years. If we want to be 90% condent that the sample mean age is within 2.5 years of the true population mean age, how many randomly selected ELAC students need to be selected? (when solving this problem round your critical value to three decimal places)