WP 1…..Introduction to Statistics Flashcards Preview

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Flashcards in WP 1…..Introduction to Statistics Deck (13)
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1
Q

continuous variable

A

can be subdivided into more and more precise units
eg height
dependent on measurement method

2
Q

discrete variable

A

only measured in whole units

3
Q

types of data:scale
interval
ratio

A

can dip below 0, multiply and division not allowed ..eg degrees
cant fall below 0 eg height , age

interval and ratio are continous variables

4
Q

ordinal

nominal

A

-order of importance (pain score`)

  • data that fits into a category (eye colour)
    • dichotomous :only 2 categories (true/false)
5
Q

types of averages
mean
median
mode

A
  • add all values and ÷ by no. of observation made (ratio and intervals)
  • value that is in middle of distribution (ordinal)
  • most frequently occurring value (ordinal)
6
Q

Basics of dsitributions:
population
sample

A
  • entire set of subjects that we want to know

- portion of pop we gather info about , this should be representative of population

7
Q

Bias

A
  • systemaic (non-random) error
    - towards the null =understates a risk/benefits
    - away from the null = overstates a risk/ benefit
8
Q

convergance

A

how representative a sample is to a population

9
Q

standard deviation

A

spread of points around mean…. measure of how dispersed data is in relation to mean
square root of variance

10
Q

variance

A

average degree to which each point differs from mean

11
Q
symbols in population for
mean
standard deviation
no.of observations
variable
A

µ

N
X

12
Q
symbols in sample for
mean
standard deviation
no.of observations
variable
A

x witha line on top of it
s
n
x

13
Q

standard error

A

shows how accurate the mean (of any given sample) from that population is likely to be compared to the true population