Central Middle School has calculated a 95% confidence interval for the mean height (u) of 11-year-old boys at their school and found it to be 56 + 2 inches. Which of the following could be the 90% confidence interval based on the same data? A) 56+ 1 B) 56 + 2 C) 56 +3 D) Without knowing the sample size, any of the above answers could be the 90% confidence interval.

Nina would like to estimate the difference in the mean amount of time students spend on math homework at her public school versus her cousin Sharon’s private school. To do so, each girl selects a random sample of 30 students from their large schools and asks the selected students how much time they spent doing math homework the previous night. Nina and Sharon would like to construct a 90% confidence interval for the true difference in the population means. Are the conditions for inference met? Yes, all three conditions for inference are met. No, the random condition is not met for both samples. No, the 10% condition is not met for both samples. No, the Normal/large sample condition is not met for both samples.

7) Suppose that in a sample of 5274 customers at a food store, 2468 food shop more than once a week. Find a 98% confidence interval for the population proportion of customers who shop more than once a week. Interpret your answer.

6) When 415 college students were surveyed, 175 said they own their car. Construct a 95% confidence interval for the proportion of college students who say they own their cars.

In the United States, 1000 residents aged 15 or older were surveyed and 870 replied that they were satisfied with the water quality. The 90% confidence interval estimate of all U.S residents satisfied with their water quality is

A professor sampled 46 students from a large university to obtain a 95% confidence interval for the proportion of students in favor of raising ASB fees. The interval was (0.356, 0.397). If the professor had used a 90% confidence interval instead, the confidence interval would have been ... A) Wider and would have a smaller chance of missing the true proportion. B) Narrower and would have a larger chance of missing the true proportion. C) Narrower and would have a smaller chance of missing the true proportion. D) Wider and would have a larger chance of missing the true proportion.

The dataset "nurses" is a random sample of 1,000 cases from “Health Care Provider Credential Data” from Washington State Open Data Portal. In the sample, there are 418 CNA's and 278 of the CNA's have expired credentials. Use the statistics from the nurses dataset to answer the following question: "With 90% confidence, what percent of all CNA's on Washington State's healthcare provider list are expired?"