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a-level core maths > Paper 2 > Flashcards

Paper 2 Flashcards

1
Q

what did Karl Pearson do

A

developed a number for correlation between -1 < r <1§
noted with the letter R
Pearson’s Product Moment Correlation PMCC

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2
Q

How to find the R value 8

A

1) press SETUP
2) Statistics (6)
3) y=a + bx
4) Type in values
5) Press AC (Statistics y = a + bx)
6) Press OPTN
7) Press 3 (Regression calc)
8) r value = r number

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3
Q

what is positive correlation

A

as one variable increases so does the other one

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4
Q

what is a strong positive correlation

A

+ 0.5 < r < + 1

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5
Q

what is a weak positive correlation

A

0 < r < + 0.5

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6
Q

what is a negative correlation

A

as one variable increases the other decreases

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7
Q

what is a perfect negative correlation

A

r = -1

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8
Q

what is a perfect positive correlation

A

r = +1

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9
Q

what is a strong negative correlation

A

-1 < r < -0.5

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10
Q

what is a weak negative correlation

A

-0.5 < r < 0

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11
Q

what is no correlation

A

no visible trend in the data r = 0

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12
Q

what is a cofounder

A

correlation caused by a third factor

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13
Q

what is regression

A

a regression line is the line of best fit

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14
Q

what is extrapolation

A

when the value lies outside the given data range, generally unreliable

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15
Q

what is interpolation

A

when the values lies inside the given data range

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16
Q

what is the formula to find the regression line

A

y = a + bx

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17
Q

what is a in y = a + bx

A

the constant term of the value of y when x = o

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18
Q

what is b in y = a + bx

A

gradient gives the increase in y when x increases by 1 unit

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19
Q

what is a mean

A

the sum of all the values divided by how many there are

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20
Q

what are the pros of the mean

A

includes every values in the calculation

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21
Q

what are the cons of the mean

A

affected by extreme values

may not be a sensible answer

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22
Q

what is a median

A

the middle value when the data is placed in order. if there are 2 middle values, find the mean of them

23
Q

what are the pros of the mean

A

isn’t affected by extreme values

24
Q

what are the cons of the mean

A

doesn’t include all of the data

25
Q

what is a mode

A

the observation that occurs most frequently

26
Q

what are the pros of the mean

A

isn’t affected by extreme values

only average used with qualitative data

27
Q

what are the cons of the mean

A

can be multiple modes or no modes

28
Q

what is a interquartile

A

upper quartile - lower quartile

29
Q

what is the lower quartile

A

look at the values below the median

30
Q

what is the upper quartile

A

look at the values above the median

31
Q

what is a standard deviation

A

the basic idea is to find the average from the mean

32
Q

how to find the standard deviation

A

1) turn on frequency
2) shift SETUP
3) press down
4) statistics 3
5) press ON 1
6) statistics 6
7) 1 variable 1
8) Type in values
9) press AC
10) press OPTN
11) Press 1-variable calc

33
Q

what are bar charts

A

for discrete data

frequency given by height of bars

34
Q

what are histograms

A

for continuous data

frequency given by area of bars

35
Q

how to calculate frequency

A

frequency = frequency density x width

36
Q

how to draw a histograms 3

A
  • frequency can only be used on the vertical axis when the groups have equal widths
  • when the class widths are equal, subtract the class boundaries to find the class widths
  • when the class widths aren’t equal divide each frequency by the corresponding class width to give frequency density
37
Q

what does a normal distribution have 4

A
  • the data follows the curve closely but not exactly
  • mean median and mode
  • symmetry about the curve
  • 50% of values less than the mean and 50% greater
38
Q

what is important the remember of the normal distribution

A

if the probability is less than the number read straight of the table, if the value is greater than the values minus the number form 1

39
Q

what was the sample mean

A

the average of a set of data

40
Q

how to find the sample mean of 1 Sample data

A
  • work out z-values
  • use the statistical table
  • to find the probability minus one from the other
41
Q

what is the standard error for a sample

A

standard deviation / sample size squared rooted

42
Q

how to find the sample mean for a SAMPLE

A

work out distribution
work out z values
minus the values

43
Q

what Is critical analysis

A

involves exploring arguments. a well constructed argument should involve:
-robust evidence
-correct reasoning
-appropriate conclusion
if an argument can’t be cleared followed it maybe because its not expressed clearly enough

44
Q

what is clarity 6

A
  • use of emotive language
  • use of vague language
  • what knowledge does the author assume the reader has
  • is the argument contradictory
  • does the author make reasonable assumption
  • are too many assumptions made
45
Q

what is selectivity of data

A

one piece of data can be convincing but a range of Data needs to considered

46
Q

what is sampling and training

A
  • in a small sample steps are taken to achieve a representative sample to draw sensible conclusions
  • representative samples are used to enable testing to tale place but with minimal timing
  • if a particular group was not represented in the sample then any conclusion cannot be applied to any members of that particular group
47
Q

what is misleading data

A
  • times scales and axes are starting points. this is chosen to be more effective in order to further their point
  • when interpreting a graph check that what appears to be shown is actually the case. conventions are that uniform scale starting from 0 are used
48
Q

what is coincidence

A
  • if two events A and B are correlated then
  • it could be coincidental
  • A could cause B
  • B could cause A
  • a third factor could cause A and B
  • when two things appear to be linked they are said to be correlated. however correlation necessarily whether there is a causal link
49
Q

what is critical analysis of models

A
  • people can be highly selective of the data used to further support their point
  • once a reporter have made up their mind it is sometimes too easy to grasp supporting evidence and to ignore any contradictory evidence
50
Q

how do you calculate a confidence interval for the mean

A
  • calculate the standard error

- a 95 % confidence interval means that 0.95 lies within 1.96 x the standard error of the mean sample

51
Q

where does 99 % of distribution lie

A

-2.58 , 2.58

52
Q

where does 95% of distribution lie

A

-1.96 , 1.96

53
Q

where does 90% of distribution lie

A

-1.64 , 1.64

a-level core maths (3 decks)

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