i need help with these questions please

Question & Private colleges and universities rely on money contributed by indadduals and corporations for their operating expenses. Much of this money is invested in a fund called an endowment, and the college spends only the interest earned by the fund. A recent survey of eight private colleges in the United States revealed the following endowments (in million of dollars. 60 2. 47.0 235.1, 490 0, 122 6, 177.5, 95.4, and 220.0. Summary statistics yield and Calculate a 50% confidence interval for the mean endowment of all private colleges in the United States. Part ac State the assumptions that are required for this interval to be valid. Part b: Construct a 9016 confidence interval. Part c Interpret the confidence interval in (by D Question 7 A Florida newspaper reported on the topics that teenagers most want to discuss with their parents. The findings, the results of a poll, showed that 46% would like more discussion about the family's financial situation, 37%% would like to talk about school, and 30% would like to talk about religion. These and other percentages were based on a national sampling of 532 teenagers. Estimate the proportion of all teenagers who want more family discussions about school. Use a 95 confidence level. Part at State the assumptions that are required for this interval to be valid. Part be Construct a 95% confidence interval. Part c: Interpret the confidence interval in (b).D Question An auditor checks a sample of 225 randomly chosen tramactions from among the thousands processed in an office. Thirty-from contain errors in crediting or debiting the appropriate account. Part a: Does this situation meet the conditions required for a confidence interval for the population proportion? Part b: Find the 95%% confidence interval for the proportion of all transactions processed in this office that have these small errors. Part c Interpret the confidence interval. Part d: Managers claim that the proportion of error is about 10%. Does that seem reasonable? D Question 9 One of the characteristics that determine success of credit cards is the average outstanding balance. Prior to extending an offer. the credit company wants to estimate the average outstanding balance. The company randomly selects 140 customers. The average monthly balance is calculated as $1,990.50 with a standard deviation of $2.833.33. Part a: Construct a 95% confidence interval estimate. Part b: Interpret the confidence interval. Part c: State the conditions required for this interval to be valid