Types of Data & Statistical Analysis (Final Exam) Flashcards
What are the two main categories of data?
- Quantitative data
2. Categorical data
What are the two sub-types of Quantitative data?
- Continuous
2. Discrete
Which sub-type of data discussed considers all values possible within a range? (i.e. shear strength of porcelain)
Continuous Quantitative data
Which sub-type of data discussed considers only certain values possible in a range? (e.g. number of decayed teeth a person has–possible values 0-32)
Discrete Quantitative data
What are the two sub-types of Categorical data?
- Nominal
2. Ordinal
What sub-type of data discussed involves data falling into a category, but there is no order to the data? (e.g. presence/absence of oral cancer, or race/ethnicity)
Nominal Categorical data
What sub-type of data discussed involves data that has specific order to it? (i.e. Never, Few times/month, Few times/week, Every day)
Ordinal Categorical data
In what 4 ways is Quantitative data is described as?
- Mean
- Median
- Mode
- SD
What type of Quantitative data is sensitive to extreme values?
Mean
What type of Quantitative data is less sensitive to extreme values?
Median
In what the 2 ways Categorical data is described as?
- Frequency
2. Percentage
What type of Categorical data is the count of a given outcome or in each category?
Frequency
What type of Categorical data is the count of a given outcome per hundred showing proportion of each category out of the total?
Percentage
Which letter is representative or Correlation?
r
What is the square of correlation (r^2) representative of?
The fraction of variation in Y explained by X.
The ____ the r^2, the better the fit of the regression line is.
Higher
“Usually states there is no difference between two groups being compared or no effect of a product or intervention; u1=u2”
H0: Test Hypothesis (null)
“Usually states that there IS a difference between two groups being compared or an effect of a product or intervention; often the one the researcher thinks is the “truth”.”
Ha
In a directional hypothesis, u1 ___u2
>
In a non-directional hypothesis, u1 ____u2
Does NOT equal
What type of error involves rejecting the null hypothesis that is actually true in the population?
Type I Error
Which letter describes the level of statistical significance and is interpreted as the maximum chance of incorrectly rejecting the null hypothesis when it is actually true?
Alpha
What type of error involves failing to reject (accept) the null hypothesis that is actually false in the population?
Type II Error
Which letter describes the probability of a type II error?
Beta
Power is calculated as _____ and is related to the sample size used in the study.
1-Beta
“The probability, assuming that the null hypothesis is true, of seeing an effect as extreme or more extreme than that in the study by chance.”
P-value
If the P-value is less than or equal to Alpha, what does this indicate?
You should reject the null hypothesis.
If the P-vaue is greater than Alpha, what does this indicate?
You should fail to reject the null hypothesis
“A range of values about a sample statistic that we are confident that the true population parameter lies”
Confidence Intervals
Researcher’s commonly set Confidence Intervals at ____%.
95%
How are Confidence Intervals interpreted?
If the data collection and analysis is repeated over and over, the CI will include the correct value 95% of the time.
“Statistical test that can be used to determine whether the mean value of a continuous outcome variable differs significantly between two independent groups (i.e. comparing the mean years of survival for implants in women vs. men to see if they differ significantly)”
T-test
What type of test assumes approximate normal distribution of the variable of interest in the groups being compared?
T-test
The __________ can be used when the outcome variable of interest is only being examined in one group (testing difference from 0 or some given value).
One-Sample T-test
The __________can be used when subjects are matched in pairs and their outcomes are compared within each matched pair (including where observations are taken on the same subjects before and after a given intervention).
Matched-Pair T-test
When comparing categorical data, the _______ test can be used to compare the proportion of subjects in each of two groups who have a dichotomous outcome (i.e. comparing the presence of periodontitis in diabetics vs. non-diabetics)
Chi-squared test
_____ is a, “statistical method that allows for comparison of several population means”
ANOVA (analysis of variance)
ANOVA uses the _____ statistic in relation to alpha to determine whether of not the null hypothesis should be rejected or not.
F-statistic
A study that compares the strengths of composite A, B and C to see if they are significantly different would be referred to as?
ANOVA (analysis of evidence)
“Situation in which a non-casual association between a given exposure and an outcome is observed as a result of the influence of a third variable.”
Confounding (usually designated a confounding variable or confounder).
A variable is a confounder if:
- It is a known risk factor for the outcome
2. It is associated with the exposure but is not the result of the exposure
How to do you evaluate if a covariate is a confounder?
1: Is it associated with exposure?
2: Is it casually associated with outcome?
If YES, then:
Step 1: Calculate Crude Association
Step 2: Calculate stratum specific association
_____ can lead us to conclude a casual relationship, when in fact, there is none or vice versa.
Confounding (confounding is NOT an “all or none” phenomenon”
