AP Exam Review Flashcards
What are two ways to increase power?
- Increase sample size
2. Increase significance level (alpha)
To get the largest power, look for the distribution with the _______p-value
Smallest
What is power?
The probability of rejecting a false Ho
When the p-value is low…
…reject the Ho.
What 4 graphs can display univariate numerical data?
Dot plot
Histogram
Stem plot
Box plot
r
Correlation coefficient
Interpret r
There is a strong/weak, pos/neg, linear association between _____ and ______.
R squared
Coefficient of determination
Interpret R squared
___% of the variation in y can be explained by x
Three characteristics of a binomial
- 2 outcomes
- Constant probability
- Fixed number of trials
What is InvNorm for?
To find the z score if you know the probability (use the area to the left)
How do you use normalcdf?
Put in the lowest z score and the highest z score
What is the formula for outliers?
Q3+1.5IQR
Q1-1.5IQR
What kind of tests can you use with numerical data/means?
One sample t test
Two sample t test
Matches pairs t test
What type of tests can you use with categorical data/proportions?
One proportion z test
Two proportion z test
Chi square test
What are 2 measures of center?
Mean
Median
What are 2 measures of spread?
Range
IQR
Standard deviation
What is a Type I error?
Ho is true, but we think Ha is true.
What is a Type II error?
Ha is true but we think Ho is true.
What is the difference between a binomial and a geometric distribution?
Geometric = count the number of trials until you get a success Binomial = count the number of successes in a fixed number of trials
What are the 3 principles you should incorporate when you design an experiment?
Control = Treat all subjects the same except for the treatment Randomization = Assign subjects to treatment groups randomly Replication = Assign multiple subjects to each treatment group
What are three types of experiments?
Completely Randomized Design
Randomized Block Design
Matched Pairs
What is another name for subjects?
Experimental units
The x variable or independent variable is called…
Explantory Variable
The y variable or dependent variable is called…
Response Variable
What are 4 ways to randomly sample people?
Simple Random Sample
Cluster
Stratified
Systematic
What is a block?
A group of subjects that are similar in some way (gender, age, etc). The subjects in each block are split apart and randomly assigned to each treatment group.
What is the difference between stratified and cluster sampling?
Stratified = groups are made so they are similar based on a characteristic (age, race, etc.). Then survey some from EVERY group.
Cluster = Groups are usually naturally occurring and are mixed. Survey a few of the groups, not all of them.
What is systematic sampling?
Start with the ___th person. Sample every ___th person.
What is Ms. Fortune’s favorite Starbucks drink?
Java Chip Frappachino :)
What are 4 types of bias?
Response Bias
Non Response Bias
Voluntary Bias
Undercoverage
A badly worded question or an embarrassing survey topic might result in _______ bias.
Response
A survey conducted by a police officer, teacher, or other authority figure might result in _____ bias.
Response
A survey in which people choose to participate might result in _________ bias. To avoid this type of bias, the researcher should randomly choose people to participate.
Voluntary
A survey conducted during homeroom or first period might miss the opinions of students who are chronically late to school. This is an example of ________________.
Undercoverage
What happens to the standard deviation of a sampling distribution as n increases?
Decreases
For the LSRL given, interpret the slope:
Predicted Exam Grade = 50 + 15 hrs studied
For every increase in 1 hour studied, on average your exam grades increases by 15 points.
For the LSRL given, interpret the y-intercept:
Predicted Exam Grade = 50 + 15 hrs studied
When you study 0 hours, your predicted exam grade is 50.
If a linear model is appropriate for a scatterplot, the residual plot shows ________________
no pattern
How do you calculate a residual?
e = actual y - predicted y
What is a residual?
The distance between a point on the scatterplot and the Least Squares Regression Line.
What is extrapolation?
Using a LSRL to make a prediction for an x value outside the range of your data. Extrapolation is not a good idea because the pattern may not continue.
What is an influential point?
A point whose removal significantly changes the LSRL.
True or False: If you add a constant to every piece of data in your data set, measures of spread do NOT change.
True
True or False: If you multiply every piece of data in your data set by n, measures of spread are also changed by a factor of n.
True
Name two statistics that are resistant to outliers and skew.
Median
IQR
Name three statistics that are non-resistant.
Mean
Standard Deviation
Range
What kind of distribution has a mean and a median that are approximately equal?
A distribution that is symmetrical
What are the 3 conditions for a one sample z test?
Random Independence (n 10)
What are the 3 conditions for a one sample t test?
Random
Independence (n30 OR
2. Original pop is normal OR
3. Graph of sample is approx normal
What are the 3 conditions for a Chi Square test?
- Random
- Categorical data
- Expected values >5
What are the 4 conditions for a Linear Regression t test?
- Random
- Linear Model is appropriate because the scatterplot shows a linear trend.
- The y-values are approx normal because a graph of the residuals is approx normal.
- Sigma of y is approx the same for all x values since the points are evenly spaced around the regression line.
As you increase the confidence level, what happens to the confidence interval?
It gets wider.
How do you calculate degrees of freedom for…
- t-test
- Chi Square GOF
- Chi Square
- LinReg t test
t test = n-1
Chi Square GOF= categories -1
Chi Square = (rows -1)(columns - 1)
LinReg t test = n-2