Sampling
Type of test?
Hypothesis Testing Steps
Hypothesis Testing Characteristics
Hypothesis Testing Theory
Descriptive & Inferential
100
How are participants selected in convenience?
Participants are selected because they are conveniently located or accessible
100
What are two examples of tests of difference?
Means (interval and ratio)
Proportions (ordinal and nominal)
100
What is the first step of hypothesis testing?
Formulation of the null hypothesis and the alternative hypothesis
100
What does the R-squared value indicate?
The strength of association between X and Y
200
What is the first step of the sampling process?
Define the target population
200
What are two examples of tests of associations?
Correlation (interval and ratio)
Proportions (ordinal and nominal) (Chi-Square tests)
200
What is your conclusion with the hypothesis when a p-value that is below alpha?
Rejection of the null hypothesis
200
When should a One Sample T-test be used?
When we want to compare the mean of one sample to a set threshold
200
What is the difference between inferential statistics and descriptive statistics?
Inferential statistics: quantities from sample data calculated to make inferences about the population being studied
Descriptive statistics: summary measures that describe your sample data
300
When is snowball sampling beneficial?
When populations are difficult to reach or identify
300
What does the p-value measure the probability of?
The probability that your result is due to chance
300
What does Simple Linear Regression analyze?
The strength of the linear relationship between variables when one is considered independent and the other dependent.
300
When should an Independent Sample T-Test be used?
When we want to compare the mean of one variable across two sub-groups in your population
300
When testing the relationship between two variables, what test should be used if our goal is to test associations with frequency distributions?
Bivariate Chi-Square Test
300
What is the predicted sales when MMprice =0, TR price =0 and there is no ad?
513.851
400
What are four examples of probability sampling?
Simple random sampling, systematic sampling, stratified sampling, cluster sampling
400
What are the two basic properties that we calculate for our sample?
- Central tendency (mean, median, mode)
- Dispersion/Spread (standard deviation, absolute frequencies, relative frequencies)
400
What do you do after you run a correlation?
Look at the significance
If it is significant look at the Pearson correlation to see strength and direction (positive/negative)
400
What test should be used if we want to compare the frequency distribution of a sample variable to a hypothesized population distribution?
Chi-Square Test
400
What does an F-Test for regression tell us?
The F-test of overall significance tells us whether our linear regression model provides a better fit to the data than a model that does not contain independent variables
400
According to this output, when “TR price in $” increases by $1, holding all else constant, what is the predicted increase in MM OJ sales?
+ 114.9
500
How do you conduct stratified sampling?
1. Divide the population into subgroups (strata).
Note: the strata don’t overlap and no one’s left out.
2. Select an independent simple random sample from each stratum.
500
What is the goal of inferential statistics?
Use characteristics of the sample to estimate characteristics of the population
In other words, use sample statistics to estimate population parameters
500
What are the two steps of the independent t-test?
Hypothesis test of equality of variance of 2 samples
Hypothesis test of difference of means
500
What are the assumptions of a Chi-Square Test?
The expected counts (Ei) has to be greater than 5 for at least 80% of the cells in the table
No cell can have an expected count below 1
These assumptions check if there is enough data for the test to be accurate
500
According to this output, when there is A Feature Ad that week, holding all else constant, what is the predicted increase in MM OJ sales?
+ 270.328