to study a presumed inverse relationship between black tea consumption and cardiovascular disease, investigators randomly selected a sample of 13,500 subjects, 50 - 64 years of age, and queried them about tea consumption and current treatment for cardiovascular disease between January 2021 and September 2021. No significant association was found between drinking black tea and having cardiovascular disease. What is the study design?

We are interested in analysing the effect of the lockout laws introduced in some areas of the Sydney CBD and nearby surrounds on the number of alcohol-related violent incidents.  Suppose we have two samples of data on the number of violent incidents in a number of local areas of the Sydney CBD and nearby surrounds. Pubs, hotels and clubs located in a subset of these areas became subject to the lockout laws when they were introduced in 2014. The first sample is from 2010 before the introduction of the lockout laws, and the second is from 2015 after the introduction of the law. The hypothesis we wish to test is that the introduction of the lockout laws reduces violent incidents in the areas in which the lockout laws were put in place.  We use a difference-in-difference model on the pooled data from 2010 and 2015. We find the following results: viol_inc hat = 33.21 (5.29) + 12.43lockout (7.01) – 4.19Yr2015 (2.98) – 3.32 (lockout x Yr2015) (1.85) N = 181, R^2 = 0.128 Where: viol_incis the…

Researchers investigate how the presence of cell phones influence the quality of human interaction.  Subjects are randomly selected from a population and divided into an experimental group that is asked to leave their phones in the front of the room and a control group that are not asked to leave their cell phones at the front of the room.  Subjects are left alone for 10 minutes and then asked to take a survey designed to measure quality of interactions they had with others in the experiment.  What statistical test is appropriate?

According to the American Lung association, lung cancer account for 28% of all cancer deaths in the US.  A new type of screening for lung cancer, computed tomography (CT), has been developed.  Medical researchers believe CT scans are scans are more sensitive than regular X-rays in pinpointing small tumors. The Cancer Center at the University of South Florida is currently conducting a clinical trial of 50,000 smokers nationwide to compare the effectiveness of CT scans with X-ray for detecting lung cancer (Today’s Tomorrows, Fall 2002).  Each participating smoker is randomly assigned to one of the two screening methods, CT or chest X-ray, and his or her progress is tracked over time.  The age at which the scanning method first detects a tumor is the variable of interest. A. Identify the data collection method used by the cancer researchers.        B. dentify experimental units of the study.  C. Identify the type of the variable measured.  D. Identify the population and sample.

The National Cancer Institute conducted a 2-year study to determine whether cancer death rates for areas near nuclear power plants are higher than for areas without nuclear facilities. A spokesperson for the Cancer Institute said, "From the data at hand, there was no convincing evidence of any increased risk of death from any of the cancers surveyed due to living near nuclear facilities." Let p denote the proportion of the population in areas near nuclear power plants who die of cancer during a given year. The researchers at the Cancer Institute have considered the null and alternative hypotheses below: А. Họ: p = value for areas without nuclear facilities Hạ: p> value for areas without nuclear facilities According to the spokesperson's statement, what is the conclusion of the National Cancer Institute? Select one of the following: Reject Ho Fail to reject Ho Reject Ha Fail to reject Ha

Acne is a common skin disease that affects most adolescents and can continue into adulthood. A study compared the effectiveness of three acne treatments and a placebo, all in gel form, applied twice daily for 12 weeks. The study's 517 teenage volunteers were randomly assigned to one of the four treatments. Success was assessed as clear or almost clear skin at the end of the 12 week period. The results of the study can be seen in the table below. Using the appropriate statistical test, determine if there is significant evidence that the four treatments perform differently. If so, how do they compare.

In an observational study it was found that people who had received the flu shot this year had better blood pressure readings, on average, than people who did not.  Can it be claimed that the flu shot is the cause of the lower overall blood pressure?  Why or why not?

In a study of 301 Hispanic women living in San Antonia, Texas, one variable of interest was the percentage of subjects with impaired fasting glucose (IFG). IFG refers to a metabolic stage intermediate between normal glucose homeostasis and diabetes. In the study, 24 women were classified in the IFG stage. The article cites population estimates for IFG among Hispanic women in Texas as 6.3%. Is there sufficient evidence to indicate the population of Hispanic women in San Antonio has a prevalence of IFG higher than 6.3%? Use 95% confidence level and the p -value method to form your conclusion. Choose the correct null and alternative hypothesis.

The Wall Street Journal asked Concur Technologies, Inc., an expense management company, to examine data from 8.3 million expense reports to provide insights regarding business travel expenses. Their analysis of the data showed that New York was the most expensive city. The following table shows the average daily hotel room rate (*) and the average amount spent on entertainment (y) for a random sample of 9 of the 25 most-visited U.S. cities. These data lead to the estimated regression equation ŷ = 17.49 +1.0334x. For these data SSE = 1541.4. Click on the datafile logo to reference the data. Use Table 1 of Appendix B. DATA file City Boston Denver Nashville New Orleans Phoenix San Diego San Francisco San Jose Room Rate ($) 148 96 91 110 90 102 136 90 82 Tampa a. Predict the amount spent on entertainment for a particular city that has a daily room rate of $89 (to 2 decimals). $ Entertainment ($) 161 105 101 142 ***** b. Develop a 95% confidence interval for the mean amount spent on…

A story spoiler gives away the ending early. Does having a story spoiled in this way diminish suspense and hurt enjoyment? A study1 investigated this question. For twelve different short stories, the study’s authors created a second version in which a spoiler paragraph at the beginning discussed the story and revealed the outcome. Each version of the twelve stories was read by at least 30 people and rated on a 1 to 10 scale to create an overall rating for the story, with higher ratings indicating greater enjoyment of the story. The ratings are given in Table 1 and stored in StorySpoilers. Stories 1 to 4 were ironic twist stories, stories 5 to 8 were mysteries, and stories 9 to 12 were literary stories. Here we measure the size of the effect on mean rating. Find a 95% confidence interval for the difference in mean enjoyment rating between stories with a spoiler and stories without.Click here for the dataset associated with this question.Round your answers to three decimal places.The 95%…