Team26

Do Carrots Improve Vision?

Team 26

Subjects

People with bad eyesight

Explanatory Variable

How many carrots are eaten

TreatmentsAmount of Carrots Eaten Daily–None (control group)

–1 cup

–2 cups

Response Variable

Eyesight chart results/improvement of eyesight

Experimental Design

Take 900 volunteers and randomly assign them to a group (2 cups of carrots daily, 1 cup of carrots daily, no carrots daily) using the computer

randomization method (explained on randomization slide). Then compare the eyesight after a month with the eyesight that they started

the experiment with.

900 volunteers

random assignment

300 people: 1 cup/daily 300 people: no carrots

300 people: 2 cups/daily evaluate eyesight after a month to check for

improvements

Control GroupOne group of people will have a carrot-free diet for duration of study

Randomization• Computer assign all volunteers with number

alphabetically

• Computer will randomly select numbers using a random number generator

• First 300 selected get treatment 1, next 300 get treatment 2, the rest (300) are the control group

• Discard repeats

• Purpose is to get groups as similar as possible

BlockingMales and females with similar(poor)

eyesight

BlindingNo blinding because eyesight will not improve just by believing that it will

improve for eating carrots

ConcernsThe volunteers might eat different

foods that could help improve/benefit their eyesight

Statistical AnaylsisPercent of

people whose vision got

worse after a month

Percent of people whose

vision got better after a

month

Percent of people whose vision stayed

the same after a month

Volunteers who ate 1 cup

of carrots a day

15% 58% 27%

Volunteers who ate 2

cups of carrots a day

6% 72% 22%

Volunteers who ate no

carrots (constant)

66% 4% 30%

ConclusionsCarrots will help maintain and/or

improve vision

Work Citedhttp://www.reocities.com/NapaValley/vineyard/9032/veggiescol/carrots.gif

http://www.nytimes.com/2005/05/03/health/03real.html?_r=1&

http://recipes.simplythick.com/joomla/images/carrots.png