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A hypothesis is an educated guess about how things work.

Most of the time a hypothesis in epidemiology is written like this: "If [Exposure] ___, then [Outcome]____ will happen.“

Your hypothesis should be testable. In other words, you need to be able to measure both “Exposure" and “Outcome."

Hypothesis

What do we mean when we say that there is an association between an exposure and

an outcome?

Associated

Tied RelatedLinked

Things that are associatedare linked in some way that makes them

turn up together.

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Connected

Suicide Higher in Areas with Guns

Smoking Linked to Youth Eating Disorders

Snacks Key to Kids’ TV- Linked Obesity: China Study

Family Meals Are Good for Mental

Health

Students Who Bring Their Lunch to

School Eat Less Junk Food

Higher Risk of Obesity Among Teens with More

Video-Game Playing

Breakfast Each Day May Keep Colds Away

Study Concludes:

Movies Influence Youth Smoking

Study Links

Iron Deficiency to Math

Scores

Study Links Physical Fitness to Academic Achievement

Proximity of Fast Food Restaurants to Schools and Adolescent Obesity

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When it comes to health-related behaviors, what are you curious about?

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• Rarely or Never Wore a Bicycle Helmet • Rarely or Never Wore a Seat Belt

• Ever Smoked Cigarettes • Ever Smoked Cigarettes Daily

• Ate Fruit or Drank 100% Fruit Juices Two or More Times per Day

• Ate Vegetables two or more times per Day

• Did Not Drink Milk• Drank Two or More Glasses per

Day of Milk• Did not Drink Soda or Pop• Drank Soda or Pop two or More

Times per Day• Ate Breakfast on 0 Days• Ate Breakfast on All 7 Days

• Physically Active at Least 60 Minutes per Day on 5 or More Days

• Participated in Muscle Strengthening Activities on 3 or More Days

• Used Computers 3 or More Hours per Day

• Watched Television 3 or More Hours per Day

• Attended Physical Education Classes

Daily• Played on at Least One Sports

Team• Played on at Least One Sports Team• Overweight• Described Themselves as Overweight • Trying to Lose Weight

• Eight or More Hours of Sleep

YRBSS health-related behaviors

• Eat school cafeteria food

• Have a sedentary lifestyle

• Have a high-fat diet

• Have a low-fat diet

• Take multivitamins

• Eat junk food every day

• Regular family meals

• Skip lunch

• Unhealthy snacks

Other possible behaviors in a hypothesis

• Drink high calorie drinks

• Drink diet soda

• Drink caffeinated drinks

• Walk to school

• Live near a fast-food restaurant

• Eat at fast food restaurant

• Fatigue (crash) during day

• Other ? ? ?

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• Parental supervision

• Texting

• Computer games

Non-health-related factors that may be used as an exposure

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• Television

• Computer time

• Seeing films with smokers

Eating fruits and vegetables

People who rarely watch TV are more likely to eat fruits and vegetables

People who eat more fruits and vegetables take more multivitamins

Physical Activity

Physical activity is associated with a longer night’s sleep

People with high academic performance are more likely to also have more physical activity

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Some variables can be either an exposure or an outcome in the

hypothesis

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“Can we decide on our own hypothesis?

Yes, with some guidance:

• Pick something that your team is genuinely curious about

• Use correct hypothesis language

• Be sure it is school appropriate

• It will be subject to approval by your Principal

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EPI Challenge

Master Proposal Form

Name of Team Member

________________

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Study Proposal: Section 1

Health-Related Behavior and Hypothesis

1a.i. Name a health-related behavior that is of genuine interest to your team and that you would like to study.

1a. ii  State why this behavior is of interest to your team.

1.a.iii State why it is a relevant topic to explore in your school.

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Study Proposal: Section 1

Health-Related Behavior and Hypothesis

1b. State a hypothesis about your health-related behavior that you would like to test. (The hypothesis must be “school appropriate” and will require the approval of your Principal.)