Week 9 Flashcards

(44 cards)

1
Q

What is biostatistics

A

The science of analyzing data and interpreting the results so that they can be applied to solving problems related to biology, health or related fields

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

What is univariate analysis

A

Describe one variable in a data set using a simplele statistics like counts, proportions and averages

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

What is multivariable analysis

A

Encompasses statistical tests such as multiple regression models that examine the relationships among three or more variables
( Confounding)

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

What is a variable

A

Any quantity that varies from one entity to another (sometime within an entity over time)
Any attribute phenomenon or event that can have different values

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

What are the two sub categories of variables

A

Quantitative and Qualitative

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

What are the two types of variables in quantitative studies

A

Discrete
Continuous

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

What are the two types of variables in qualitative sutides

A

Nominal
Ordinal

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

What is the normal variable

A

No intrinsic or logical order or value
You can assign numbers to different categories
But they do not have any other numeric properties

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

What is Ordinal variables

A

Intrinsic value but with no clear or equal differences between levels
Mild vs moderate vs severe pain
We can 5 is better than 4 etc but we cannot attribute being measured 4 is not two times larger than 2

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

How do we display qualitative data

A

Pie chart
Bar chart
Frequency table

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

Who created the first pie chart

A

Florence Nightingale

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

What is a numeric variable

A

Any positive real number depends on the nature of the variable can be expressed in decimals
Meaningful numeric scales
Age blood pressure # of friend temperature

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

What is continuous variables

A

Can take any value
Blood pressure
Temperature
Can be plotted as a line

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

What is discrete of variables

A

Can take a finite or limited number of variables
Age in year
No of drinks
Can be plotted as dot

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

What is the Interval variable

A

Interval is the difference is meaningful
No natural zero ( when you have 0 it doesn’t mean nothing)
Arbitrary zero: Interval tempertaure 0 dosen’t mean no 0

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

What is ratio variable

A

Ratio is meaningful
Zero means absence of attribute ( is natural)
Temperature in Kelvin 0 means absolute 0
Blood pressure a dead person
Age
Income

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

What are the three aspects of central tendency

A

mean, mode, median

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

What is the point of histogram

A

Gives you an idea of distribution of all data

19
Q

What is a symmetric normal distribution

A

Mean meidan and mode are the same
This can be Bp
Weight
Height

20
Q

What is negatively skewed normal distribution

A

Mode is on the high side
Mean is low
Marks in modules and tutorial
Means that most people are on the positive end of normal distribution and the outliers are on the other side

21
Q

What is positively skewed

A

The mean is the higher side because you have a few people on the high side like salary where the outliers skew it to the right but most people make a low or moderate income

22
Q

What is the range

A

The difference between the minimum and maximum

23
Q

What are the quartiles

A

Mark three values split the data in half
Q1 is hald of the lower half
Q2 is the median
Q3 is the middle of the upper half

24
Q

How do you calculate interquartile range

25
What are the main points in a boxplot
The first line on the box is Q1 The middle line in the box is the Median The last line on the box is Q3 The end of the left side is q1-1.5*IQR The end of the right side is q3+1.5*IQR There are outliers are the dot we don't want to include them
26
How do you caculate variance
You add all your data points minus the mean square it and divide by the amount of numbers
27
How do you calculate standard deviation
Is the square root of the variance
28
How do you calculate standard error
Dividing the standard deviation by the total number of observations and then dividing by the total number of observations square rooted
29
How is normal curve split up
68% 95% 99.75% Each middle part is 34.1% Then out is 13.6% Then 2.1% Then 0.1%
30
How do you see how many are measured
You add mean + 1 sigma and -1 sigma Then 2 etc see where you are on the graph
31
What does a confidence interval do
Provide information about the expected value of a measure in a source population based on the measured value in a study population
32
What does a 95% confidence interval do
Means that 5% of the time the confidence interval is expected to miss capturing the true value of a measure in the source population
33
What is comparative statistics
You are comparing 2 groups Comparing the main factors between exposed and unexposed in cohort studies We can not just look at the calculated values ( these are estimates from samples subject to random sampling error)
34
What is inferential statistics
Techniques that use statistics from a random sample of a population to make evidence-based assumptions (inference) about the values of parameters in the population as a whole
35
What is hypothesis testing
To test an explicit statement or a hypothesis about a population parameter
36
What is the null hypothesis
There is no difference between the two or more values being compared
37
What is the alternative hypothesis
There is a difference between the two or more populations being compared
38
What are the steps in hypothesis testing
1. Take a random sample from the population of interest 2. Set up two competing hypotheses ( based on research questions) 3. Use sample statstics (mean,frequency) 4. Determine if the null hypothesis is really true
39
What is the p value
Determine whether the observed sample supports the null
40
When do you reject the null hypothesis
If the p value is less than 0.02 or usally less than 0.05
41
When do you accept the null hypothesis
0.1 and 0.9
42
How is the p-value caculated
From observed data based on pertinent test statistic
43
What is parametric test
Assumes the variables being examined have particular distributions Inferential methods are based on types of distributions Often normally disturbuted
44
What is a nonparametric test
Does not make assumptions about the distributions of reponses Used for ranked variables and when the distribution of a ratio or interval variable is non-normal