Statistics Flashcards
First stage of experimentation?
Form hypothesis.
Second stage of experimentation?
Test hypothesis.
Third stage of experimentation?
Analyze results.
Fourth stage of experimentation?
Draw conclusions.
When are statistics used during experimentation?
Analyzing results.
We organize and analyze data to…
draw conclusions from it.
null hypothesis
assumption that there will be no difference between groups
alternate hypothesis
assumption that there will be a difference between groups
If there is a significance difference between the groups, we…
reject the null hypothesis and accept and alternate hypothesis.
quantitative data
numerical measurements or quantities
qualitative data
categorical measurements
population
large group that would be difficult to experiment on
sample
small subset of a population that can be experimented on
descriptive statistics
describes our data by looking at certain trends/patterns throughout a sample
inferential statistics
makes generalization to a larger population with the data from a sample
Descriptive statistics are measures of…
central tendency and variablility.
measures of central tendency
single statistic that best describes the center of a distribution of data
Examples of measures of central tendency are…
mean, median, and mode.
measures of variability
statistics that tell us how different the data are from each other
Examples of measures of variability are…
range and standard deviation.
mean
most representative number from a dataset
standard deviation
amount of variance around the mean; how different the numbers are
Normal distribution is represented by…
a bell curve.
Descriptive statistics describe…
our data using measures like mean and standard deviation.
Inferential statistics examine…
the means and variability of each group in order to tell us if they are different from each other.
Sampling error arises because…
no sample can perfectly mimic the population.
standard error of the mean (SEM)
indicates how well the standard deviation of a sample represents the standard deviation of the population
law of large numbers
larger the sample size, the more probably that the sample mean will be close to the population mean
central limit theorm
large samples will approximate the normal distribution
standard error bars
illustrate the standard error of the mean (SEM) on a graph
Standard error bars show…
the variation from the mean.
If standard error bar does not overlap with bar, then…
they significantly different from each other.
confidence interval
range of values so defined that there is a specified probability that the value of a parameter lies within it
If an experiment has a 95% confidence interval, then…
if we replicated the same experiment with the same amount of participants 100 times, we would expect 95/100 times the group mean would fall within confidence interval.
t-tests
used to determine if there is a statistically significant difference between two sets of data
We calculate the t-statistic value by…
comparing the mean of two data sets and dependency on degree of freedom.
T-statistic leads to…
p-vale which decides whether or not the difference is statistically significant.
