1.3 Introduction to Experimental Design

1.3 Introduction to Experimental Design

Multiple Choice

We want to know if students taking probability and statistics plan to go to college. There are 4 sections of the class offered. We select 5 students from Mrs. Schmitt's 4th period class at random. What is the sample frame?

Sample Frame- individuals from whisch the sample was taken

• All students taking Probability and Statistics

• 5 students in Mrs. Schmitt's 4th period

• All students in Mrs. Schmitt's Probability and Statistics course.

• Students in the other 3 probability and statistic courses.

Multiple Choice

Your friend's score on an intelligence test

• Nominal

• Ordinal

• Interval

• Ratio

Multiple Choice

The number of hours you spent studying each day during the past week

• Nominal

• Ordinal

• Interval

• Ratio

• Simple Random Sample- every member of the population has an equal chance of being selected

• Systematic-Number all individuals, randomly select starting point, then survey every k^th member.

• Cluster-Divide population into clusters, sample every member in the randomly selected cluster

• Stratified- Divide population into strata, sample some from each strata

Multiple Choice

To determine the most popular type of cake among all the students at your school, ask your entire math class.

• Cluster Sample

• Simple Random Sample

• Stratified Random Sample

• Systematic Sample

Multiple Choice

Farmer Joe randomly picks 100 trees using a random number generator to estimate the number of apples produced by his apple trees. This is ______________ sampling.

• Simple

• Stratified

• Cluster

• Systematic

Multiple Choice

Mrs. Trahan samples her class by selecting 5 girls and 7 boys.  This type of sampling is called?

• Stratified
• Systematic
• Simple
• Cluster

Open Ended

To determine the most popular type of cake among all the students at your school, how could we conduct a systematic sampling?

Open Ended

To determine the most popular type of cake among all the students at your school, how could we conduct a stratified sampling?

Fill in the Blank

Observations from the entire population are used in a _____________, while observations from part of the population are used in a _______________.

Fill in the Blank

An _________________ is conducted in a way that doesn’t change the response or the variable being measured. In an ______________, a treatment is used to inflict a possible change in the variable being measured.

Example of Experimental Design

Fill in the Blank

Using numbers to represent real-world objects is the procedure of ______________.

Multiple Choice

An elementary school teacher wanted to see how extra exercises would improve students’ grades. She constantly assigned extra exercise problems to one of her classes, but for her other class she just gave the regular assignments. At the end of year she compared the two classes.

Is this an observational study or an experiment?

• Observational study

• Experiment

Multiple Choice

Which technique for gathering data do you think would be most appropriate for the following study?

Study of the effect of stopping the cooling process of a nuclear reactor.

• Sampling

• Experiment

• Simulation

• Census

Multiple Choice

Which technique for gathering data do you think would be most appropriate for the following study?

Study of the amount of time college students taking a full course load spend watching television

• Sampling

• Experiment

• Simulation

• Census

Multiple Choice

Which technique for gathering data do you think would be most appropriate for the following study?

Study of the effect on bone mass of a calcium supplement given to young girls.

• Sampling

• Experiment

• Simulation

• Census

Multiple Choice

Which technique for gathering data do you think would be most appropriate for the following study?

Study of the credit hours load of each student enrolled at your college at the end of the drop/add period this semester.

• Sampling

• Experiment

• Simulation

• Census

Fill in the Blank

When a random process is used to assign each member to one of the treatments, it is a ________________.

Fill in the Blank

If someone thinks that he or she is receiving treatment and response favorably but in fact no treatment is given to this person, it is called a ______________

Fill in the Blank

A group of members having certain common features that might affect the treatment forms a _________.

Fill in the Blank

A process of first forming these groups and then randomly assigning each member in the group to one of the treatments is called a ______________

Example of Randomized block design

Fill in the Blank

To account members for the influence of other known or unknown variables that might cause changes in response, we use a _______________.

Fill in the Blank

To assign members to the two treatment groups in order to prevent bias in selecting members for each group, we use ______________.

Fill in the Blank

To reduce the possibility that the differences between the two groups occurred by chance alone, we ______________ the experiment.

Multiple Choice

Example 2: If elementary school teacher in Example 1 teaches only one class, she could randomly assign her students into groups and give extra exercise problems to one group but not the other. Then at the end of the year she can compare the performance of the two groups. This is one example of a

• completely randomized experiment

• randomized block experiment

• observational study

• experiment

Multiple Choice

Which technique of gathering data do you think might be the most appropriate for the following studies?

a) Effect of a large scale earthquake

• simulation

• sampling

• experiment

• census

Multiple Choice

b) Amount of time high school students spend online each week

• simulation

• sampling

• experiment

• census

Multiple Choice

c) Effect of a new medicine for a certain heart disease

• simulation

• sampling

• experiment

• census

Multiple Choice

d) Whether wedding guests are allergic to the planned main course.

• simulation

• sampling

• experiment

• census

Multiple Choice

Some potential pitfalls of a survey include: _______________ when no response is obtained from some individuals,

• nonresponse

• truthfulness

• faulty recall

• hidden bias

• voluntary response

Multiple Choice

___________________ when the respondents may not be telling the truth,

• truthfulness

• faulty recall

• hidden bias

• vague wording

• interviewer bias

Multiple Choice

________________ when the respondents may not remember the truth,

• voluntary response

• interviewer bias

• faulty recall

• hidden bias

• vague wording

Multiple Choice

_________________ when the question may be worded in such a way as to elicit a certain response,

• nonresponse

• truthfulness

• faulty recall

• hidden bias

• vague wording

Multiple Choice

___________________ when the words such as "frequently." "sometimes," and "quite good," mean different things to different people,

• nonresponse

• voluntary response

• interviewer bias

• hidden bias

• vague wording

Multiple Choice

___________________ when the attitudes of the interviewer might influence responses,

• faulty recall

• voluntary response

• interviewer bias

• hidden bias

• vague wording

Multiple Choice

and _________________ when the individuals with strong feelings about a subject are more likely that others to respond.

• faulty recall

• voluntary response

• interviewer bias

• hidden bias

• vague wording

The study of the cause-and-effect relationship between two or more variables can be complicated but a lurking variable for which no data have been collected but that nevertheless has influence on other variables in the study, or by confounding variable when the effects of one variable cannot be distinguished from the effects of the other.

Multiple Choice

Example 4

What is the potential pitfall of the data collected as described?

a) A school principal calls ten students to his office. He writes down each student's name and asks whether he or she has cheated on any tests in the past year.

• Truthfulness

• Nonresponse

• Faulty Recall

• Interviewer bias

Multiple Choice

b) A survey about changing the graduation requirements was conducted by mailing survey forms to students. A drop box for completed forms was available by the main entrance of the school

• Nonresponse

• Hidden bias

• Voluntary response

• Vague Wording