WP 1…..Introduction to Statistics

Question 1

continuous variable

Answer 1

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

Question 2

discrete variable

Answer 2

only measured in whole units

Question 3

types of data:scale
interval
ratio

Answer 3

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

interval and ratio are continous variables

Question 4

ordinal

nominal

Answer 4

-order of importance (pain score`)

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

Question 5

types of averages
mean
median
mode

Answer 5

• 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)

Question 6

Basics of dsitributions:
population
sample

Answer 6

• entire set of subjects that we want to know

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

Question 7

Bias

Answer 7

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

Question 8

convergance

Answer 8

how representative a sample is to a population

Question 9

standard deviation

Answer 9

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

Question 10

variance

Answer 10

average degree to which each point differs from mean

Question 11

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

Answer 11

µ
∂
N
X

Question 12

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

Answer 12

x witha line on top of it
s
n
x

Question 13

standard error

Answer 13

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