Flashcards in Summarising and presenting data Deck (26)

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1

## What are the 2 main categories of data?

###
Qualitative / categorical

Quantitative / numerical

2

## What types of qualitative data are there?

###
Unordered (male/female)

Ordered (small/ medium / large)

3

## What types of quantitative data are there?

###
Discrete (number of children in family)

Continuous (SBP)

4

## How would you examine the make-up of a sample of patients?

### Using a frequency table

5

## When is cross-tabulation useful?

### Way of exploring whether two qualitative variables have any association (e.g sex and smoking)

6

## What can bar charts and pie charts be used for?

### To show proportions or percentages graphically

7

## What is the median?

### central value, such that 50% of the data falls at either side

8

## What is the lower quartile?

### Chosen to place 25% of the data below it

9

## What is the upper quartile?

### chosen to place 75% of the data below it

10

## What is the inter-quartile range?

###
IQR

the difference between the 3rd and 1st quartiles, and quantifies the spread of the sample.

11

## What is the mean?

### 1/n(sigma)xI

12

## What is variance?

### s2 = 1/(n-1) (sigma) (xi-mean)2

13

## How do the mean and median relate to each other when the sample of the data have a reasonable symmetrical distribution?

### mean = median

14

## How do the mean and median relate to each other when the sample is positively skewed?

### Mean >median

15

## How do the median and mean relate to each other when the sample is negatively skewed?

### Mean < median

16

## What is a histogram a representation of?

### The frequency distribution

17

## If a histogram is shifted to the right it indicates?

### Negative skew

18

## If a histogram is shifted to the left it indicates?

### positive skew

19

## When is a doxplot useful?

### When there are not many data points

20

## How is positive skew seen in a box plot?

### the distance from Q1 ro the median is much less from the median to Q3

21

## What graph should be used to compare to quantitative variables directly?

### scatterplot

22

## When shouldn't the mean be used to indicate the central value of the sample?

### When the data is heavily skewed

23

## When are box-plots inappropriate?

### With very small sample sizes (3-4 points)

24

## What are response variables?

### these measures are used to describe the condition of an individual/subject (also called outcome measure or dependent variables?

25

## What are explanatory variables?

### Those measures that might explain the condition of an individual/subject (also called predictor or independent variables)

26