A research group claims that 20% of patients with dementia never develop full Alzheimer's. In a simple random sample of 1,000 patients with dementia, 150 report that they never develop full Alzheimer's. Test the claim of the research group using a 5% significance level.

Over the past few decades, public health officials have examined the link between weight concerns and teen girls' smoking. Researchers surveyed a group of 273 randomly selected teen girls living in Massachusetts (between 12 and 15 years old). After four years the girls were surveyed again. Sixty-three said they smoked to stay thin. Is there good evidence that more than thirty percent of the teen girls smoke to stay thin? Correctly identify the null and alternative hypotheses:

In 2015, a survey found that 38% of Americans were supportive of online education for elementary and secondary education. With the increase in contagious viruses, it is of interest if this proportion has changed. In a 2019 poll, 51% of 1028 Americans were supportive of online education for elementary and secondary education. At the 10% significance level, do the data provide sufficient evidence to conclude that the percentage of all American adults who support online education for elementary and secondary education has changed from what was believed in 2015? Choose the choice that gives the null and alternative hypothesis.

Mood variation is related to photoperiod in some people, and the likelihood of depression increases in the winter months. As a result, people often assume that suicide rates increase in winter. A study in Finland (Valtonen et al. 2006) divided the year 1997 into equal halves and compared the number of suicides in “winter” (24 September to 19 March) and “summer” (remainder of year). Out of a total of 1636 suicides, 766 were in winter and 870 were in the summer. Based on these data, estimate the proportion of suicides that occurred in winter, assuming that the suicides were independent. Are the data compatible with a greater suicide rate in winter than summer, based on a 95% confidence interval?

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?"