An orthopedic surgeon observes that many of his patients coming in for total knee replacement surgery played organized sports before the age of 10.  He plans to collect more extensive data on participation in organized sports from four patients undergoing knee replacement surgery and to report the findings.  Identify the type of study proposed.

Alcohol abuse has been described by college presidents as the number one problem on campus, and it is an important cause of death in young adults.  How common is it?  A survey of 10,904 randomly selected U.S. college students collected information on drinking behavior and alcohol-related problems.  The researchers defined “frequent binge drinking” as having five or more drinks in a row three or more times in the past two weeks.  According to this definition, 2486 students were classified as frequent binge drinkers.  Construct and interpret a 99% confidence interval for the proportion of students who are classified as binge drinkers. (Use the four-step process.)   What would you include in "State" from the 4-step process?

A Chinese cell-phone manufacturer exclusively uses robots in one of its factories. A random test run results in 23 defective assemblies out of 500. Does this data suggest that the true percentage of defectives is less than 5%? Use NATDRC.

According to the most recent General Social Survey, 70% of adults watch TV nightly. A researcher believes that the proportion of college students who watch TV nightly is less than this. To test this claim the research samples 400 college students and finds that 276 watch TV nightly. At the 0.05 level of significance does this data provide evidence to suggest that the proportion of college students who watch TV nightly is less than 70%?

A physical therapist claims that 75% of people lose their balance if they close their eyes while standing on one foot. A gymnast feels that the rate is less than 75%. To test this, she randomly selects 100 people and finds that 80 of them lose their balance while standing on one foot. To determine if these data provide convincing evidence that the proportion of people who lose their balance while standing on one foot and closing their eyes is less than 75%, 150 trials of a simulation are conducted. The gymnast is testing the hypotheses: H0: p = 75% and Ha: p < 75%, where p = the true proportion of people who will lose their balance while standing on one foot and closing their eyes. Based on the results of the simulation, what is the estimate of the P-value of the test?   A) 0.1133 B) 0.17 C) 0.887 D) 0.92

Alcohol abuse has been described by college presidents as the number one problem on campus, and it is an important cause of death in young adults.  How common is it?  A survey of 10,904 randomly selected U.S. college students collected information on drinking behavior and alcohol-related problems.  The researchers defined “frequent binge drinking” as having five or more drinks in a row three or more times in the past two weeks.  According to this definition, 2486 students were classified as frequent binge drinkers.  Construct and interpret a 99% confidence interval for the proportion of students who are classified as binge drinkers. (Use the four-step process and Table A to get your z* value.)   Using the interval that you calculated in the last question, conclude in context for the question.

If a researcher failed to use a random sample, how would this affect the research conclusion?   If a researcher failed to use random assignment, how would this affect the research results?

In a survey of 1220 adults in a​ country, 58​% said the​ country's leader should release all medical information that might affect their ability to serve. The study is   observational, an experiment, because it   applies does not apply a treatment to the adults.

In 2016, the New York Times reported that the average American spent 50 minutes per day on Facebook, as compared to an average of 42 minutes per day reading, exercising, or actually socializing combined. You suspect that this gap has widened over the years, and collect a random sample of 100 people. For 50 of them (again, randomly chosen from your sample), you track their time spent on Facebook; you track the other 50 peoples’ total time spent reading/exercising/socializing. (a) Say the 2016 figures regarding Americans’ time allotments still hold true. If the population standard deviation for minutes using Facebook is 12.5 minutes, and the population standard deviation for minutes spent on reading, exercising, and socializing (referred to from here on as ”Other” activities) is 8 minutes, what are the expected value and the standard error of the difference between the average amount of time spent on Facebook and the average amount of time spent on Other activities computed from a sample…

Hypertension is when an adult is classified as having high blood pressure (above 130 systolic blood pressure is considered hypertension). Researchers want to know the proportion of adult North Americans (above age of 18) that have hypertension. Based on a study of 3532 adult North Americans, 1219 of them were classified as having hypertension.