Solution case 1 a since there is randomization and

Solution
Case 1:
a)
Since there is randomization and some aspect of control (some are
given the medicine while the others are not), this is an experiment. Even
though you cannot tell if the two groups have similar make-up, the other
two criteria are met, so this is a well-designed experimental study.
b)
Control group: those who did not get medication
Treatment group: those who did get medication
Effect being studied: whether medication decreases headache pain
Case 2:
a)
This is an observational study. There are no controls for who used
fertilizer and who did not, and subjects are not randomized.
b)
The effect being studied is whether fertilizer makes lawns green.
Factors other than fertilizer, such as watering, can affect the colour of a
lawn. Without good control, it is hard to know what causes any effect.
Your Turn
1.
A researcher interviews people as they leave the gym and finds that
they get fewer colds compared to people who do not go to the gym.
a)
Why is this an observational study?
b)
What could be done to turn this into an experimental study?
2.
A botanist is studying the effects of acidity on rate of growth. She
grows one group of plants using water with neutral pH. She grows each
other group using water with increasingly acidic pH levels.
a)
Which are the control and which are the experimental groups?
b)
Why do you think groups of plants were used rather than one single
plant for each pH level?
214 MHR • Chapter 5

Example 2
Survey Questions
Conducting surveys is another way to collect primary data. Surveys are less
controlled than experiments, but a well-written survey can provide useful
information. The following survey is being distributed to 100 students:
School Feelings Survey
Name: Age:
10–12
12–16 16–17 Over 18
Male Female
Cell phones No cell phones
Gender:
1. Would you like to have the freedom to use your cell phone in class or would you
rather be alone with no communication?
Math Drama English
2. Which of the following is your favourite subject?
No Yes
3. Do you think it’s important for students to attend church?
Good Great Fantastic Awesome
Pretty good
4. How do you like the new cafeteria menu?
Do not like them Like them
5. How do you like the new school logo and mascot at the school?
Check to make sure the survey asks appropriate questions.
a)
Is the survey anonymous? Why might anonymity be important?
b)
Are the choices for ages appropriate and clear? If not, how can you fix
this section? Why is this important information to collect?
c)
Is #1 a leading question? If so, explain why this is a problem and rewrite
the question.
d)
Do any questions provide a limited number of options? If so, rewrite
the question.
e)
Does the survey ask any personal questions that people might prefer
not to answer?
f)
Is the rating scale in #4 a well-written scale? If not, rewrite it.