Unit 7 lesson 1&2 (types)

Unit 7 lesson 1&2

Critique and evaluate reports based on data and how the data were collected.

Recognize the purposes of and differences among sample surveys, experiments, and observational studies.

Statistical Design (take notes)

• Surveys are sets of questions given to people to seek their responses.

• Experimental studies collect data by directly influencing something to determine how another thing is changed.

• Observational studies collect data without influencing things directly.

What is the difference between an observational study and an experimental study?

• In an observational study, you collect the data without influencing things directly to answer your question. In an experimental study, you directly influence things and collect data to answer your question.

Multiple Choice

Survey, experiment, or observational study:

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​What subject do students like the best?

• Survey

• Observational study

• Experimental study

Multiple Choice

Survey, experiment, or observational study:

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When left unsupervised, will children eat a bowl of candy?

• Survey

• Observational study

• Experimental study

Multiple Choice

Survey, experiment, or observational study:

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Does listening to classical music while studying increase test scores?

• Survey

• Observational study

• Experimental study

Multiple Choice

A study of 1,000 people aged 20–30 asked how much television each person watches each night and how each person would rate their energy level in the evenings.

Is this study a survey, observational study, or experimental study?

• Survey

• Observational study

• Experimental Study

Open Ended

Does this mean that watching television for at least 2 hours every night lowers energy in the evening? Explain your reasoning.

Possible answer

No. Sample reasoning: Since the data was collected through a survey, only an association can be determined and not a causal relationship. It’s possible that some people may have lower energy in the evening for other reasons and they watch a lot of television since they do not have energy for other activities.

Multiple Choice

What type of sweetener do flies prefer? A scientist divides the flies into different groups and gives each group only water with a certain type of sweetener in it for 3 days. The scientist then does a test on each group to see how well the flies can fly through a maze.

• Survey

• Observational study

• Experimental study

Open Ended

What type of sweetener do flies prefer? A scientist divides the flies into different groups and gives each group only water with a certain type of sweetener in it for 3 days. The scientist then does a test on each group to see how well the flies can fly through a maze.

Is the experiment good or bad? Explain why.

Possible response

The design is bad. The experiment does not address the original question. It might test how the sweeteners affect the flies’ ability to fly, but not their preference.

Open Ended

What type of sweetener do flies prefer? A scientist puts the same amount of each sweetener into different bowls of water and counts the number of flies that drink from each bowl in 4 hours.

Is the study good or bad? Explain your reasoning.

Possible response

The design is good. The flies should be attracted to the sweetener they like and drink more often from that bowl.

A researcher discovers that the diameter of a person’s pupil in their eye is directly related to how beautiful they find the image they are looking at. The researcher wants to know whether reading an article about climate change influences people’s perception of pictures of a city in terms of beauty. 100 people have volunteered to be a part of the study.

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​The volunteers are split into 2 groups by a random process. One group will read the article and the other will not. Everyone will then look at the city pictures and the diameter of their pupil will be measured while they look at the pictures.

Multiple Choice

Match each of the options to the type of study.

The volunteers are split into 2 groups by a random process. One group will read the article and the other will not. Everyone will then look at the city pictures and the diameter of their pupil will be measured while they look at the pictures.

• Survey

• Observational study

• Experimental study

A researcher discovers that the diameter of a person’s pupil in their eye is directly related to how beautiful they find the image they are looking at. The researcher wants to know whether reading an article about climate change influences people’s perception of pictures of a city in terms of beauty. 100 people have volunteered to be a part of the study.

​

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​The volunteers are split into 2 groups by a random process. One group will read the article and the other will not. Everyone will then look at the city pictures and the diameter of their pupil will be measured while they look at the pictures.

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​What does a random process mean exactly?