lecture 3&3b Flashcards
scientific findings arent supposed to be accepted based on
who the scientist is or who is funding the research
what is discovery science
science that is describing nature based on qualitative date (no experiments)
what is hypothesis based science
science that explains nature using quantitative data (using experiments)
what are the seven steps of the scientific method
- make observations
- ask questions
- form a hypothesis
- make a prediction
- test the prediction (plan and perform experiments to collect data)
- interpret data
- draw conclusions
what is a hypothesis
educated guess/tentative explanation
a hypothesis must be
falsifiable (can be right or wrong)
should you say that the hypothesis is right
no you have to say that the data supports the hypothesis
what is a theory
a well sustained explanation for a set of verified hypotheses
independent variable
variable being manipulated
dependent variable
variable that is being tested
control variable
variable that is the same in the experimental and control group
control group
group that is used to compare to the experimental group (doesn’t get treatment)
how do we avoid biases
neither the researchers or groups know who got the drugs or the placebo
what is a replicate and why is it important
experiment being done multiple times to see the variability in the data obtained and to verify the experiment
how do ethics play into science
don’t change data, write everything down to allow reproduction and take care of living things and avoid contamination of viruses
what are descriptive statistics*
stats that describe your data and tell you what is going on in your experiment
what are the measures of central tendency*
mean, median, mode
what is the mean*
average
what is the median*
the middle value/midpoint
what is the mode*
the most common number in the data set
how do you know that you have a normal distribution*
the graph is symmetrical
the mean, mode and median are identical
what happens when the mean is standardized to 0*
the majority of the data points should be grouped around the average
what is the drawback to taking the mean*
outliers will skew the average
what does having the data points bunched together vs spread out mean*
when bunched together: there is low variability
when spread out: high variability
what is the variance*
relative distance between the data points and the mean (s^2)
what is the standard deviation*
how far apart numbers are in the sample (SD)
what is the main advantage of the sd compared to s^2*
sd is in the same units as the thing youre measuring
what is standard error*
how accurate the results of your sample are compared to the general population (SE)
what are inferential statistics*
stats that use collected data and make inferences about the field
what are the two types of hypotheses*
null and alternate
what is a null hypothesis*
opposite of alternate hypothesis
hypothesis you are testing with stats
“there will be no difference”
what is an alternate hypothesis*
opposite of null hypothesis
tests your prediction
what are the two types of the alternate hypothesis*
non-directional and directional
what is a non-directional hypothesis*
predicts that there will be a difference but wont state the direction or magnitude of the difference
what is a directional hypothesis*
predicts that the difference will be bigger or smaller
what is alpha*
the level of significance of data/estimate of the probability that the result has occurred by accident or chance
what is the value of alpha that we will use*
0.05 or 5%
what is the p-value*
probability that you get your sample result assuming that the null hypothesis is true
what happens when the p-value is smaller than alpha*
the data supports the alternate hypothesis
what happens when the p-value is bigger than alpha*
the alternate hypothesis is most likely untrue
