Midterms Quiz Compilation Flashcards
The correlation between coefficient between X and –X
-1
What does significant result in a chi-square test imply?
It implies that the sample is not representative of
the population
How many cases need to appear in one category for chi-square?
5
What type of data do you need for a chi-square test?
CATEGORICAL
For the chi-square test to be effective the expected value for each cell in the contingency table has to at least
5
The null hypothesis in the chi-square test states that
THE ROWS AND COLUMNS IN THE TABLE
ARE ASSOCIATED
Which statement is not correct about the chi-square test statistic?
A VALUE CLOSE TO 0 WOULD INDICATE
EXPECTED COUNTS ARE MUCH
DDIFFERENT FROM OBSERVED COUNTS
A researcher asked 933 people what…..
CHI-SQUARE TEST
What must be true about the expected values in a chi-square test?
GREATER THAN OR EQUAL TO 5
Analysis of variance is a statistical method of comparing the —- of several populations
MEANS
When incidence rates are available, comparing rates using a ratio measure of association is best don’t with a odds ratio
FALSE
An odd ratio greater than 1 indicates a negative association between exposure and outcome
FALSE
The prevalence ration can be used in a case control study or any study where the outcome data is prevalence
FALSE
January 1, 2003. On June 5, 2003, it was discovered that 75 of those gym patrons currently had gym-related injuries. After June 5, the remaining injury-free patrons were enrolled in a cohort study, classified as machine-users (n=1000) and free-weight users (n=425), and followed for 3 years. 85 machine-users and 15 free-weight users became injured in the 3 years. All follow- up stopped on exactly June 5, 2006. Assuming complete ascertainment and no drop-outs: Calculate the odds ratio for injury among machine users
2.5
Fourteen of the volunteers who were given the new medicine have an upset stomach, and 42 of the volunteers who were given the new medicine do not have an upset stomach. In volunteers who did not take the medication, two people have an upset stomach and 83 do not have an upset stomach. Calculate the
relative risk of having an upset stomach (event) after taking the new medicine (exposure)
10.4
Fourteen of the volunteers who were given the new medicine have an upset stomach, and 42 of the volunteers who were given the new medicine do not have an upset stomach. In volunteers who did not take the medication, two people have an upset stomach and 83 do not have an upset stomach. What is the Probability in non exposure group?
0.024
The first way that the odds ratio can be calculated is by comparing those with the outcome to those without the outcome
TRUE
Relative Risk is often used when the study involves comparing the likelihood, or chance, of an event occurring between two groups. Relative Risk is considered a descriptive statistic and an inferential statistic; as it does not determine statistical significance.
1ST statement is true and 2ND is false
Relative Risk utilizes the probability of an event occurring in one group compared to the probability of an event occurring in the other group. It requires the examination of two dichotomous variables, where one variable measures the event (occurred vs. not occurred) and the other variable measures the groups (group 1 vs. group 2)
BOTH STATEMENT ARE TRUE
A way to present disease occurrence using a denominator hat is comprised of person time and has some advantages over using rates
INCIDENCE RATIO
Fourteen of the volunteers who were given the new medicine have an upset stomach, and 42 of the volunteers who were given the new medicine do not have an upset stomach. In volunteers who did not take the medication, two people have an upset stomach and 83 do not have an upset stomach. What is the Probability in exposure group?
0.25
A way to present disease occurrence using a denominator hat is comprised of person time and has some advantages over using rates
INSIDENCE DENSITY RATIO
To use ANOVA you should have more than 3 observations
TRUE
ANOVA helps to answer a hypothesis by splitting up the sources of variability
TRU
Analysis of variance is a statistical method of comparing the — of several populations
MEANS
The —- sum of squares measure the variability of the observed values around their respective treatment means
ERROR
A one way ANOVA will tell you that at least two groups were different from each other but it won’t tell you which groups were different
TRUE
ANOVA provides a statistical test for determining whether there is enough evidences to accept the null hypothesis that all man equal
FALSE
To determine whether the test statistic of ANOVA is statistically significant. It can be compared to a critical value. What two pieces of information are needed to determine the critical valued.
SAMPLE SIZE, NUMBER OF GROUPS
It is the needed to determine the computed F value
MSTr
the —- sum of squares measures the variability of the sample treatment means around the overall means
TREATMENT
What is needed to solve for trtdf?
k
The pearson correlation technique works best with the linear relationships.
TRUE
Correlational analysis is unable to tell how much one variable will change if another variable changes a certain
TRUE
A non-directional hypothesis predicts a negative correlation between two variables
FALSE
R and rs are symbols representing two different types of correlation coefficient
TRUE
The correlation coefficient between X and –X is
-1
If X is measured in your and X is measured in minutes, then correlation coefficient has the unit.
NO UNIT
A positive and a negative relationship may have the same strength
TRUE
In scatter diagram, if most of the points lie in the first and third quadrants, the coefficient of correlation is
Positive
The value of the coefficient of the correlation r lies between
-1 and 1
If the points on the scatter diagram show no tendency either to increase together or decrease togher the value of r will be close to
0
If the points on the scatter diagram indicate that as one variable increases the other variable tends to decrease the value of r will be
NEGATIVE
The correlation coefficient is the —- of the two regression coefficients
GEOMETRIC MEAN
When the ratio of variations in the related variables is constant, it is called
LINEAR CORRELATION
If both variable X and Y increase or decrease stimultaneously, then the coefficient of the correlation will be
POSITIVE
If one item is fixed and unchangeable and the other term varies, the correlation coefficient will be
ZERO
