Chapter #4 - 09/20/24 Flashcards
how to get a good sample
what is a synonym for “good sample” ?
representative study
what are dome examples of research studies ?
- sample surveys
- randomized experiments
- observational studies
what do we mean by a “properly chosen sample” ?
refers to a subset of a population that is selected in a way that accurately represents the larger group
why is a properly chosen sample important ?
this is important in research and statistics to ensure that conclusions drawn from the sample are valid for the entire population
what are some characteristics that makes a chosen sample good ?
- Be Representative
- Avoid Bias
- Be Random
- Be Large Enough
what do we mean by “be representative” ?
It should reflect the characteristics of the whole population (e.g., in terms of age, gender, income, etc.).
what do we mean by “avoid bias” ?
The selection process should not favor certain outcomes or groups within the population.
what do we mean by “be random” ?
Each member of the population should have an equal chance of being selected, reducing the likelihood of selection bias.
what do we mean by “be large enough” ?
The sample size should be sufficient to provide reliable results, considering the variability within the population
how do we preform a sample survey ?
a subgroup sample of a larger population is questioned on a set of topics, and responds what applies best to them
do sample surveys contain intervention or manipulation ?
no intervention or manipulatiiion of the respondents, simply asked to answer some questions
what do randomized experiments do ?
they measure the effect of manipulating the environment in some way
describe a “randomized experiment” :
manipulation is assigned to participants on a RANDOM basis
describe a “explanatory variable” :
the feature that would explain the response (in experiments this is the deature being manipulated)
define “response variable” :
outcome of intrest
what does randomization help with ?
randomization helps to make the groups approximately equal in all respects except for the explanatory variable
EXAMPLE QUESTION :
a trainer wants to investigate how the amount of exercise done by a person affects their resting heart rate. the resting heart rates of people who exercise different amounts are measured and compared
what is the respose variable ?
resting heart rate
EXAMPLE QUESTION :
a trainer wants to investigate how the amount of exercise done by a person affects their resting heart rate. the resting heart rates of people who exercise different amounts are measured and compared
what is the explanatory variable ?
amount of exercise
TRUE OR FALSE
the response variable is CHANGING DUE TO the explanatory variable
TRUE
when comparing response and explanatory variables to independent and dependent variables… which is which ?
independent = explanatory
dependent = response
EXAMPLE QUESTION :
a teacher wants to know if the temperature of the classroom affects student’s ability to focus. different temperatures are set in the room, and student’s focus levels are observed
what is the explanatory variable ?
different temperature
EXAMPLE QUESTION :
a teacher wants to know if the temperature of the classroom affects student’s ability to focus. different temperatures are set in the room, and student’s focus levels are observed
what is the response variable ?
student’s focus level
EXAMPLE QUESTION :
a gardener is intrested in whether giving plants more water makes them grow taller. plants are watered with differnt amounts, and their heigh is measured
what is the response variable ?
height of plant
EXAMPLE QUESTION :
a gardener is intrested in whether giving plants more water makes them grow taller. plants are watered with differnt amounts, and their heigh is measured
what is the explanatory variable ?
amount of water
a teacher wants to know if the number of hours students sleep before a test affects their performance. students report how many hours they slept the night before, and their test scores are recorded
what is the explanatory variable ?
students’ hours of sleep
a teacher wants to know if the number of hours students sleep before a test affects their performance. students report how many hours they slept the night before, and their test scores are recorded
what is the resopnse variable ?
test scores
define observational studies :
resembles an experiment, but manipulation occurs naturally, not imposed
TRUE OR FALSE
you cannot assume the explanatory variable is the only one responsible for any observed differences in the response variable
TRUE
TRUE OR FALSE
case-control study attempts to include an appropriate control group
TRUE
what is a case-control study ?
is a type of study used in research to compare two groups of people:
Cases – People who have a certain condition or disease.
Controls – People who do not have the condition or disease.
what are meta analyses ?
quantitative review of a collection of studies all done on a similar topic
what can combining information lead to in a meta-analyses ?
can lead to emergence of patterns or effects not readily seen in the individuals studies
what is a meta-analyses ?
combines the results of many different studies on the same topic to find an overall conclusion
how do we make mate-analyses ?
It takes data from each study, analyzes it together, and helps researchers see patterns or trends that individual studies might miss
what is the goal of a meta-analyses ?
The goal is to get a clearer, more reliable answer to a question by looking at all the available evidence instead of just one study
what is a case-study ?
in-depth examination of one or a small number of individuals
TRUE OR FALSE
case studies are descriptive ?
TRUE
TRUE OR FALSE
case studies require statistical methods
FALSE
case studies do not require statistical methosd
what is a unique quality about case studies ?
case studies generally cannot be extended to any person or situation other than the one studied
what type of study is the following question?
“patients who visit a clinic to help them stop smoking are given a chioce of two treatments : undergoing hypnosis or applying nicotine patches. the percentages who quit smoking are compared for the two methods. is this study a survery.”
a) survey
b) experiment
c) observational study
d) case study
c) observational study
why is the following question a observational study ?
“patients who visit a clinic to help them stop smoking are given a chioce of two treatments : undergoing hypnosis or applying nicotine patches. the percentages who quit smoking are compared for the two methods. is this study a survery.”
because patients were allwed to chose their treatment method rather than having it assigned
what type of study is the following question?
“a large company wants to compare two incentive plans for increasing sales. the company randomly assigns a number of its sales staff to recieve each kind of incentive and comapres the average change in sales of the employees under the two plans.”
a) survey
b) experiment
c) observational study
d) case study
b) experiment
why is the following question an experimental study ?
“a large company wants to compare two incentive plans for increasing sales. the company randomly assigns a number of its sales staff to recieve each kind of incentive and comapres the average change in sales of the employees under the two plans.”
because the incentive methods are randomly assigned
explain whether a survey or a randomized experiment would be most appropriate to find out about the following :
“who is likely to win the next presidential election”
survey
because we only need to question people about their preferences and not manipulate their environment
explain whether a survey or a randomized experiment would be most appropriate to find out about the following :
“whether the use of nicotine gum reduces cigarette smoking”
randomized experiment
because we need to randomly assign som people to use the nicotine gum and others to a “control group,” perferably using a placebo gum
is this a survey, an experiment, an observational study, or a case study ?
“researchers ask a large group of first-year university students to complete a questionnaire about their stress levels, study habits, and the amount of sleep they get each night. the researchers then analyze the response to identify common trends.”
survey
how do we know that the following example is a survey ?
“researchers ask a large group of first-year university students to complete a questionnaire about their stress levels, study habits, and the amount of sleep they get each night. the researchers then analyze the response to identify common trends.”
because surveys are more focused on finding common trends across a large group of people
how do we differentiate surveys in compairison to other studies ?
Surveys are more focused on finding common trends across a large group of people. They collect data from many participants and help identify patterns, such as popular opinions, behaviors, or preferences within a population.
is this a survey, an experiment, an observational study, or a case study ?
“a researcher spends several months dcumenting and interviewing a single family after they move to a new country to better understand how they adapt to cultural changes and the challenges they face.”
case study
how do we know that the following example is a case study ?
“a researcher spends several months dcumenting and interviewing a single family after they move to a new country to better understand how they adapt to cultural changes and the challenges they face.”
because :
- not generalizing it to the general population
- interviewing a group of people
- not looking for common trends
Case studies, focus on a deep, detailed exploration of a single case or a small number of cases.
how do we differentiate case studies vs other studies ?
They are not primarily aimed at finding common trends but rather understanding the unique aspects or complexities of a particular situation, individual, or group.
