I need help answeing these problems

Question 6 (3 points) J Saved As the number of degrees of freedom for a t distribution increases, the difference between the t distribution and the standard normal distribution 0 becomes larger @ becomes smaller 0 remains the same 0 cannot be determined from the information given Question 7 (3 points) Suppose that you want a 95% confidence interval estimate of a population mean with a margin of error of 2 or less. What sample size is needed if the population mean is known to be 11? Question 8 (3 points) In a survey of a random sample of 1,000 registered voters, 450 people in the samp favor a particular candidate. What is the 95% confidence interval estimate for the proportion of the population of registered voters who favor the candidate? 0 0.430 to 0.470 0 0.419 to 0.481 0 0.424 to 0.476 0 0.400 to 0.500 Question 9 (3 points) A manufacturing process is monitored closely. In the past, 10% of the parts produced were defective. The operations manager wishes to estimate the population proportion of defective parts with a margin of error of 0.04 or less. How large a sample size is needed for a 95% level of confidence? Question 10 (3 points) A random sample of 225 observations from a population with a standard deviation of 75 is selected. The sample mean is 180. What is the 95% confidence interval for the population mean? 0 170.2 to 189.8 Q 175.0 to 185.0 Q 171.8 to 188.2 0 173.6 to 186.4