Review_Types of Studies

Which of these statements is true about both an observational study and an experimental study?

• They both consider an entire population.

• They both include collecting data.

• They both include a control sample.

• They both directly influence the subjects studied.

Clare is interested in what students at her school think of school lunches. She sets up a table at the school cafeteria and has volunteers fill out questionnaires about school lunch. a. What type of study is Clare designing?

• Survey

• Observational

• Experiment

Answer explanation

Survey

Clare is interested in what students at her school think of school lunches. She sets up a table at the school cafeteria and has volunteers fill out questionnaires about school lunch. b. How could her design be improved to collect data that would be better for answering the question of interest?

Answer explanation

1. She should use a random sample of students (not just those she finds in the cafeteria) to get a more representative sample.

Clare is curious about the most popular sports among high school students at her school. She decides to ask the soccer team about their favorite sports. What is problematic about the way Clare selected her sample?

Answer explanation

She is only asking students on the soccer team, so there will be a bigger chance that they will prefer soccer. This sample would not be representative of all the high school students

Do years of regular running affect joint health? The medical records of a group of 500 individuals, half of whom are regular runners and half of whom are not, are studied to determine their joint health the description of the study design with the type of study being conducted. What type of study is this?

• Observational Study

• Survey

• experimental study

1. How do voters feel about the governor of their state? A group of 200 randomly selected voters in the state are asked to share their opinions. What type of study is this?

• Observational Study

• Survey

• an experimental study

Does pepper spray help prevent deer from eating plants? A selection of 1000 plants in areas where deer are found are sprayed with pepper spray, and another 1000 plants are left alone. Both groups of plants are monitored for consumption by deer What type of study is this?

• Observational Study

• 1. Survey

• an experimental study

Match the description of the study design with the type of study being conducted. How do voters feel about the governor of their state? A group of 200 randomly selected voters in the state are asked to share their opinions.

• a survey

• an observational study that is not a survey

• an experimental study

Select all designs that describe an observational study that is not a survey.

• 100 randomly selected adults are asked if they buy organic groceries.

• 50 adults are provided organic groceries, and another 50 adults are provided with conventional groceries for a year. Their health changes are recorded.

• 50 adults are asked whether they exercise at least 150 minutes each week. Another 50 adults are asked whether they spend more than 20 hours a week sitting. The health history of both groups is recorded.

• 100 adults at a grocery store are randomly selected. 50 of them are asked how much they spent at the grocery store and how that compares to their average grocery bill. 50 of them are asked what they purchased and how that compares to the purchases they regularly make at the grocery store.

• 50 adults volunteer to have a pint of blood drawn every 2 months. Another 50 adults volunteer to have a pint of blood drawn every 3 months. The health differences are recorded.

A survey conducted in a gym revealed that all members' blood pressure was within the normal range for their age. A researcher wants to know if regular exercise affects blood pressure. How could the researchers design an experiment to determine the effects of exercise on blood pressure?

Answer explanation

Randomly assign 50 people to a group that has their blood pressure taken before and after they are asked to exercise for 20 minutes. Assign 50 people to a group that has their blood pressure taken before and after they are asked to watch a 20-minute exercise video. Compare the blood pressure data from before and after the exercise or watch the exercise video