PART 1 - Descriptive Stats
What are measures of central tendency? (List them and explain what they tell us.)
mean median mode - where the data concentrate
What are z scores? What do they help us with?
standardized values; they allow us to compare apples to apples
What is the difference between a t test and a z test?
t test is used when we don't know the population sd
What is the equation for a line?
y = mx + b
What is an outlier? How do we determine if an observation is an outlier?
An observation that is beyond the range or most observations; greater than +3 sd away from the mean or less than -3 sd away from the mean.
What are measures of dispersion? (List them and explain what they tell us.)
sd, variance, range - they tell us about the variability of the data
What's a test statistic? Give an example.
t value, z value, f value. We compare it to a critical value to determine statistical sig.
In class, we learned about two main types of t tests. What are they?
Paired and independent
Explain what a regression analysis is used for.
Determining which variables sig predict an outcome variable; making predictions; quantifying relationships between variables.
How do we compute descriptive statistics using Excel?
What is a pivot table?
it's a table that allows us to organize data. we can have multiple variables and report things like the frequency of these observations.
What's a p value? What does the P stand for? What does it help us with?
Probability; it's the probability of observing the data we have, given the null hypothesis is true. It helps us determine statistical sig.
Explain what an interval estimate is and how to compute it.
A point estimate +/- MOE. It tells us, with a certain degree of certainty, a range where the true population parameter is.
The adjusted R^2 value for a regression is .28. Intrepret this value.
28% of the variance in the outcome variable can be explained by this model.
Why do we care about probability distributions?
They help us compute probabilities, the foundation of statistics :D
When we make a graph or data visualization, what are some things we should do?
label axes, title, label units, be cognizant of colors
What is a null hypothesis?
Hypothesis that says there is no difference/no effect.
List at least two types of distributions we talked about this term.
normal, standard normal, uniform, exponential, Poisson ....
A predictor, x, is statistically significant in a regression. Its coefficient is 10. Explain how to interpret this.
A 1 unit increase in x is associated with an increase of 10 in y, on average.
List three functions you learned in Excel this term.
=average()
=norm.s.dist()
=formulatext()
What percentage of data do MOST observations fall?
68, 95, 99 ish
What does it mean for something to be statistically significant?
There is an effect!
If I want to compare two groups to see if they differ, how do I do this?
use a t test or a z test
In addition to running a regression to determine the relationship between two variables, what else should I do?
explore your data! Plot it; compute descriptive statistics
What is the probability that a deer walks in Annemarie's yard during our Zoom hangout?
:D :D :D :D