module 2 visualing data abd outliers

Question 1

bar graphs are a popular way to summarize which type of data

Answer 1

categorical data.

Question 2

is bars represent mean score in each category lines (called error bars) may be shown on top of bars to represent____

Answer 2

standard deviation

Question 3

histograms are used to depict what kind of data

Answer 3

scale data.

Question 4

if data is skewed, which measure of central tendency would be used to best describe data

Answer 4

median, because it takes extreme values info account but is not greatly impacting by them since it is in the middle.

Question 5

why would a frequency polygon be used over a histogram?

Answer 5

can be useful when comparing multiple groups as adding multiple lines to one growth is easier to interpret than multiple bars.

Question 6

a one way scatter plot

Answer 6

used a single acid to display the relative position of each data point in a group. this type of figure can be used with categorical or scale data, can be presenting horizontal or vertically.

Question 7

box plots

Answer 7

only has one axis, they show a summary of the data instead of each data point.

the center depicts interquartile range. lines or whiskers projecting from the box on either side extend to the adjacent values( the most extreme observation in the data set that are no more than 1.5 times the height of the box beyond either quartile) anything beyond the adjacent values are considered extreme values and are plotted as individual dots

Question 8

when can a box plot be used

Answer 8

where there are too many overlapping data points and that would be difficult to interpret as a scatter plot or one way scatter plot

Question 9

what type of data would you use for a two way scatter plot

Answer 9

scale variables can also depict the relationship between two scale variables

Question 10

line graphs

Answer 10

similar to two way scatter plots in that they represent the relationship between two scale variables how ever for line graphs each point on the x axis has a corresponding y value, which is not a requirement for scatter plots

Question 11

what’s an outlier

Answer 11

something unusual or different or outside the norm

Question 12

how would you identify potential outliers

Answer 12

by visualizing my data. extremely positive or negative values are easy to spot in box plots, scatter plots, and histograms

Question 13

what constitutes and outlier?

Answer 13

• values that are more the two standard deviations above or below the mean
• values that are more than 1.5 times the IQR above Q3 or below Q1 ( values outside of whiskers in a box plot)

Question 14

what is a research population?

Answer 14

the group of objects events people procedures or observations that a researcher is interesting in studying

Question 15

dependent variable

Answer 15

what is being measured or the outcome of a study

Question 16

approaches to sampling

Answer 16

random sampling and non random sampling

Question 17

random sampling

Answer 17

random selection is used to choose people, objects, events or observations to be included in each sample, each often of interest has an equal change of being included with the sample

Question 18

none random sampling

Answer 18

the items included in the study are selected for a reason(proximity, feasibility) non probability sampling

Question 19

which graph type is best for showing changes over time?

bar chart
line graph
pie chart
histogram

Answer 19

line graph, they are good for showing trends or patterns across time points, like monthly case numbers or yearly vaccination rates

Question 20

which chart is best for showing the frequency distribution of a continuous variable

Answer 20

histogram, they show often values fall into specific ranges, ideal for continued variables like height, blood pressure or income

Question 21

true or false a bar chart can be used to display both categorical and numerical data

Answer 21

true

Question 23

true or false line graphs should only be used for categorical variables

Answer 23

false, they are used for continuous or ordinal data across a time axis- not categorical labels

Question 24

what is discrete data and what kind of visualization should i use for it

Answer 24

discrete data are countable separate values, cannot be broken into smaller pieces, no decimals or fractions eg number of people in a household

use bars charts or pie charts don’t use histograms

Question 25

what is continuous data and what visualization would I use for it

Answer 25

These are measurable values, that can be broken down into fractions or decimals. Eg height or weight blood pressure temperature Use histograms, line graphs or scatter plots

Question 26

Would a number of prescription meds someone takes be discrete or continuous

Answer 26

Discrete

Question 27

Would systolic blood pressure be discrete or continuous

Answer 27

Continuous

Question 28

Would number of er visits per year be discrete or continuous

Answer 28

Discrete

Question 29

How to cho see e correct graph or statistical test depending on

Answer 29

Type of variable - categorical, ordinal, continuous Number of groups What you're trying to compare

Question 30

Best graph type for categorical nominal data

Answer 30

Bar chart or pie chart eg gender blood type

Question 31

Best graph for ordinal data

Answer 31

Bar chart or boxplot if numeric eg pain scale satisfaction level

Question 32

Best chart for one continuous variable

Answer 32

Histogram, line graph, scatter plot or boxplot eg weight income time

Question 33

Best graph for 2 continuous variables

Answer 33

Scatter plot eg bmi vs blood pressure

Question 34

What statistical test would you run if you are comparing 2 groups and its continuous outcome

Answer 34

Independent t test eg compare average bmi for males vs females

Question 35

What statistical analysis would you use if you are comparing 3 or more groups with continuous outcome

Answer 35

ANOVA eg comparing cholesterol levels across the ss age groups

Question 36

What statistical test would you use to look at the relationship between 2 continuous variables

Answer 36

Correlation or regression eg Time spent exercising and stress level

Question 37

What statistical analysis would you usebti compare proportions with categorical variables

Answer 37

Chi square test eg compare smoking rates by gender

Question 38

What statistical test would you use to predict one variable from another

Answer 38

Regression eg predict weight from calorie intake

Question 39

Four types of bias in research

Answer 39

Sampling bias Survivorship bias Response bias Recall bias

Question 40

This bias occurs when each member or item of the relevant population does not have an equal chance of ending up in the sample, or selection bias

Answer 40

Sampling bias, eg only picking people at one location

Question 41

This bias occurs when participants give answers they believe the researcher wants to hear or what they think are socially acceptable answers

Answer 41

Response bias eg on a survey asked about sexual behaviour or alcohol consumption they may lie

Question 42

This bias occurs when individuals or objects leave the study and the researcher continuous to measure the remaining participants without considering those that left

Answer 42

Survivorship bias eg a study exploring 12 week excercise program to see if it removes your risk of falls, but the ones who fell dropped out skewing the results

Question 43

This bias occurs when participants do not remember past events accurately or omit details

Answer 43

Recall bias eg asking mother their comfort levels giving birth years after they've given birth

Question 44

True or false histograms are for distributions not relationships

Answer 44

True