Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Epidemiology SJSM > Block 4 Quiz > Flashcards

Block 4 Quiz Flashcards

1
Q

Describe the use of a chi-square test

A

It measures the distribution between TWO categorical variables & compares the proportions of two or more categorical data sets to see if there’s statistical significance

  • Independent variable can be two or more groups (i.e treatments)
  • Dependent variable 2 or less groups (true/false)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

It measures the distribution between TWO categorical variables & compares the proportions of two or more categorical data sets to see if there’s statistical significance

  • Independent variable can be two or more groups (i.e treatments)
  • Dependent variable 2 or less groups (true/false)

Describe the statistical test

A

Chi-squared test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Key words associated with what statistical test?:

Two categorical variables
Two/+ independent variables
Two/- dependent variables
Compares proportions
Determines statistical significance.

A

Chi Square test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Measuring statistical significance of the proportion of adults with lung disease in clinics A, B, & C at a certain point in time

What Statistical test will you use?

A

Chi-Square test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Measuring statistical significance of the proportion of people with diabetes in four different ethnic groups.

What statistical test will you use?

A

Chi-square test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the use of an ANOVA/F-test

A

analyzes the variance, it determines if there’s a statistically significant difference between two or more groups by comparing the means.
- Independent variable (manipulated by researcher)
- Dependent (mean)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a one-way F-test/ANOVA?

A

ONE independent variable
ONE dependent variable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Mean height of women in clinics A, B, &C

What is the stat test, the independent, & the dependent variables

A

One way ANOVA/F-test
Independent = Women
Dependent = Mean height

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Mean height of women & men in clinics A, B, &C

What is the stat test, the independent, & the dependent variables

A

Two-way ANOVA/F-test
Independent (Women & Men)
Dependent (Mean height)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a TWO way ANOVA/F-test?

A

TWO independent variable
ONE dependent variable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

(Pearsons correlation coefficient)

r = +1

A

Positive correlation
increase in y = increase in X
(vise versa)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

(Pearsons correlation coefficient)

r = -1

A

Negative correlation
decrease in y = decrease in x
(vise versa)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

(Pearsons correlation coefficient)

r = 0

A

NO correlation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

(Pearsons correlation coefficient)

r = 0.9

A

Weak positive correlation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what’s the correlation?

A

r= +1
Positive correlation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what’s the correlation?

A

r= -1
Negative correlation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what’s the correlation?

A

r= 0
NO correlation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what’s the correlation?

A

r= 0.9
Weak correlation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the use of a t-test?

A

It calculates the difference of the means of two samples & is used to make confidence intervals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the use of a one sampled t-test?

A

calculates whether sample mean is different then the populations mean

p> 0.05 reject null
p< 0.05 can’t reject null

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the use of a two sampled t-test?

A

calculates whether sample mean of two different groups taken from the same population differs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the use of an unpaired t-test?

A

For independent samples, it calculates whether sample mean of two different groups sampled at the same time is different

Null = group mean is equal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the use of a paired t-test?

A

For dependent samples, it calculates whether the sample mean of the same group sampled at two different times is different

Null= group mean is equal at both times

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Describe variance

A

The sum of the squared deviations from the mean divided by the total number of values

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Variables:

Describe independent variable

A

Doesn’t depend on other variables so it can be manipulated by the researcher
(i.e dosage of a drug given to a treatment group)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Variables:

Describe dependent variable

A

Depends on other variables so it can’t be manipulated
(outcome)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Doesn’t depend on other variables so it can be manipulated by the researcher
(i.e dosage of a drug given to a treatment group)

A

Independent variable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Depends on other variables so it can’t be manipulated
(outcome)

A

Dependent variable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Variables:

Describe discrete variables

A

Whole number values (number of ____)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Variables:

Describe Continuous variables

A

Any number (weight, distance, temperature etc)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Variables:

Describe categorical variables

A

Variables with categories

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Variables:

Describe Nominal Categorial variables

A

Categories without any order ( smoker vs non smoker or male vs female)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Variables:

Describe Ordinal Categorical variables

A

Ordered categories (min/mod/severe)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Describe regression

A

It means making an equation to represent the relationship between a dependent (Y/outcome) & independent (X/exposure) variables

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Describe logistic regression

A

Dependent variable is categorical
- Simple (1 independent)
- Multiple (more than 1 independent)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Dependent variable is categorical
- Simple (1 independent)
- Multiple (more than 1 independent)

A

logistic regression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

It means making an equation to represent the relationship between a dependent (Y/outcome) & independent (X/exposure) variables

A

regression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Ordered categories (min/mod/severe)

A

Describe Ordinal Categorical variables

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Categories without any order ( smoker vs non smoker or male vs female)

A

Describe Nominal Categorial variables

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Variables with categories

A

Describe categorical variables

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Describe linear regression

A

Dependent variable is continuous
- simple (1 independent)
- multiple (more than 1 independent)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

r= +1

A

positive correlation

43
Q

r= -1

A

Negative correlation

44
Q

r= 0.9

A

strong correlation

45
Q

r= 0

A

NO correlation

46
Q

Describe the z-score

A

It compares populations with different means & standard deviations

47
Q

z-score for a 95% CI is

A

1.96

48
Q

z-score for a 97.5% CI is

A

2.24

49
Q

z-score for a 99% CI is

A

2.58

50
Q

Describe confidence intervals

A

A range of standard deviations that we’re ____% sure our data will fall into

51
Q

How does sample size impact CI?

A

Larger sample sizes mean narrower CI
(small p-value aka more significant)

52
Q

Wider CI indicates what about CI?

A

Less statistical significance

53
Q

Describe a type 1 error

A

H0/Null is rejected when it’s actually true

54
Q

H0/Null is rejected when it’s actually true

A

Type 1 error

55
Q

Describe a type 2 error

A

H0/Null isn’t rejected when it’s actually false

56
Q

H0/Null isn’t rejected when it’s actually false

A

Describe a type 2 error

57
Q

Describe statistical power

A

The formula is 1-B (type 2 error)
it represents the probability of correctly rejecting the H0/Null

58
Q

How can you increase statistical power

A

Increase sample size

59
Q

Describe what bimodal distribution represents

A

There are two subgroups in the populations

60
Q

Describe this distribution

A

Bimodal, there are two subgroups within the population

61
Q

Describe what Positive skew distribution represents

A

A right tailed skew
mean < median < mode

62
Q
A

A positive skew (right)
mean < median < mode

63
Q

Describe a negative skew distribution

A

Left tailed
mean > median > mode

64
Q
A

Negative skew (Left)
mean > median > mode

65
Q

Describe what the standard error of the mean means?

A

It’s the deviation of the sample’s mean from the populations mean

Increasing standard deviation & decreasing sample both increase chance of SEM!

66
Q

How can you reduce SEM?

A

Decrease standard deviation & increase sample size

67
Q

Formula for SEM

A
68
Q

What does standard deviation describe?

A

It describes variability or dispersion of the data in relation to the mean

69
Q

68% translates to how many standard deviations

A

1SD

70
Q

95% translates to how many standard deviations

A

2 SD

71
Q

99.7% translates to how many standard deviations

A

3 SD

72
Q

Formula for standard error of proportion

A

𝑺𝑬(𝒑)=√(𝒑(𝟏−𝒑)/𝒏)

73
Q

Describe what the standard error of proportion tells us

A

measure of the precision of our estimate

74
Q

a small standard error indicates what?

A

a precise estimate

75
Q

What stat test?:

Numerical data + 1 group

A

One-sample t-test

76
Q

What stat test?:

Numerical data + 2 groups dependent on each other

A

Paired t-test

77
Q

What stat test?:

Numerical data + 2 groups independent on each other

A

unpaired t-test

78
Q

What stat test?:

Numerical data + over 2 groups independent on each other

A

ANOVA

1independent = One-way anova
2 independents = two-way anova

79
Q

What stat test?:

Categorical data + 1 group

A

z-test

80
Q

What stat test?:

Categorical data + 2 or more groups independent on each other

A

Chi-Square test

81
Q

What is the best way to minimize the chances of a Type I error in a diagnostic ?

A

Increase the specificity of the test

82
Q

A researcher is looking at the effect of a new medication upon blood pressure. She concludes that the results of her study are that the medication does affect blood pressure. What best describes her conclusion?

a) The results of her study are not valid
b) She has accepted the null hypothesis
c) The power of her study was >95%
d) The p-value for the relationship is <0.05
e) She has accepted the alternative hypothesis

A

e) She has accepted the alternative hypothesis

83
Q

A researcher is setting up an experiment. She generates two hypotheses: first, that the medication will not lower blood pressure; and second, that the medication will lower blood pressure. What is her null hypothesis?

A

The medication will not lower blood pressure

84
Q

What factors increase power?

A

1) bigger sample size
2) variability of observations
3) larger effects of interest
4) greater significance (narrow CI/small p-value)

85
Q

Researchers are looking at whether or not silicone implants cause breast cancer. They are 80% confident tat their sample size of 250 will detect a difference in breast cancer rates, if in fact one does exist. What does this 80% confidence represent?

a) The power of the test
b) The false positive rate
c) An alpha error rate of 80%
d) The false negative rate
e) A beta error of 80%

A

a) The power of the test

86
Q

What’s the stat test?:

categorical data 2 paired groups

A

McNemars test

87
Q

What test:

Quantitative variable + 2 groups

A

t-test

88
Q

What test:

Ordinal variable + 2 groups

A

Mann Whitney test

89
Q

What test:

Categorical variable + 2 or more groups

A

chi-square

90
Q

What test:

Ordinal variable + paired data

A

Wilcoxon test

91
Q

What test:

Ordinal data + more than 2 groups

A

Kruskal Wallis test

92
Q

What test

Quantitative variable + paired data

A

paired t-test

93
Q

What test

Quantitative variable + over 2 groups

A

f-test/ANOVA

94
Q

A researcher looks at the cholesterol level in men as compared to women. She is trying to determine whether or not there is a significant difference in the proportion of men with elevated cholesterol as compared to women. What is the most appropriate test?
a) Regression
b) T-test
c) ANOVA
d) Correlation
e) Chi-square

A

e) Chi-square

95
Q

A physician is studying the effects of drug A and drug B on cognitive performance in Alzheimer patients. He administers a memory test to two groups of subjects (those taking drug A and those taking drug B) and compares their mean scores. Which of the following statistical tests would be most appropriate for this purpose?
a) T-test
b) Chi-squared test
c) Paired T-Test
d) ANOVA
e) Multiple regression

A

a) T-test

96
Q

A researcher measures the cholesterol level of three demographic groups: Caucasian, Asian, and African American. What statistical test is used to compare the mean cholesterol level of these three groups?
a) Regression
b) Chi-squared test
c) T-Test
d) ANOVA
e) Correlation

A

d) ANOVA

97
Q
A

Strong positive correlation
r= 0.8 to 1

98
Q
A

Weak positive correlation
r = 0.2 to 0.5

99
Q
A

Strong negative correlation
r = -0.8 to- 1

100
Q
A

No correlation r = 0 to 0.2

101
Q
A

Moderate negative correlation
r =-0.5 to -0.8

102
Q
A

Weak negative correlation
r= -0.2 to -0.5

103
Q

A researcher found that as cigarette smoking increased, cancer rates increased. How are these two variables related?

A

Positive correlation

104
Q

A study of 100 women finds that as the cholesterol level increases, the blood pressure does not change. How are these variables related?

Zero correlation

A

Zero correlation

Epidemiology SJSM (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions