Paper 1 - Data/statistics

Question 1

what are measures of central tendency ?

Answer 1

averages of the data
mean, median and mode.

Question 2

what are the advantages and disadvantages of mean ?

Answer 2

• it is affected by outliers.
• it uses every value in the data, so represents the data well.

Question 3

what are the advantages and disadvantages of median ?

Answer 3

• less effected by outliers.
• does not account for the distance between values.

Question 4

what are the advantages and disadvantages and mode ?

Answer 4

• can be used for nominal and ordinal data.
• when there is more than one mode it does not reflect the centre of data well.

Question 5

what are measures of dispersion ?

Answer 5

the spread of data
range, variance and standard deviation

Question 6

what are the advantages and disadvantages of range ?

Answer 6

• easy to calculate
• effected by extreme values

Question 7

what is variance ?

Answer 7

measurement of the spread between numbers in a data set.
standard deviation squared

Question 8

what is standard deviation

Answer 8

the square root of variance
how dispersed the data is from the mean

Question 9

what are the advantages and disadvantages of variance and standard deviation

Answer 9

• all values are taken into account
• complex to calculate

Question 10

what do bar charts represent ?

Answer 10

nominal data

Question 11

what do histograms represent ?

Answer 11

continuous data

Question 12

what to line graphs represent ?

Answer 12

continuous data

Question 13

what do pie charts represent ?

Answer 13

nominal data

Question 14

what do scatter graphs represent

Answer 14

correlational data

Question 15

what does ∝ mean

Answer 15

proportional to

Question 16

what are inferential statistics ?

Answer 16

procedures for drawing logical conclusions about the target population that the sample was drawn from.

Question 17

what’s the observed value ?

Answer 17

the value produces after applying an inferential test formula.

Question 18

what’s probability ?

Answer 18

the measure of the likelihood that an event may occur.

Question 19

what is the significance level ?

Answer 19

the level of probability at which it has been agreed to reject the null hypothesis. 0.05.

Question 20

what’s a type one error ?

Answer 20

when the researcher rejects the null hypothesis that is true.

Question 21

what’s a type two error ?

Answer 21

when the researcher accepts a null hypothesis which is not true.

Question 22

What’s quantitative data and its advantages/disadvantages ?

Answer 22

Data in numbers.
-Its easier to analyse because data is numerical which can be summarised using descriptive statistics (averages and graphs). This makes it easier to draw conclusions from the study as the data is represented clearly.
-It oversimplifies reality and human experience as it suggests that there are simple answers.

Question 23

What’s qualitative data and its advantages/disadvantages ?

Answer 23

Non numerical data, e.g. pictures or words.
-Represents the true complexities of human behaviour because they’re not reduces to numbers.
-Provides rich detail of how people think and behave. This increases validity.
-More difficult to detect patterns and draw conclusions from because of the large variety of information collected.

Question 24

What are the 3 levels of data and what do they mean ?

Answer 24

nominal- categories
ordinal - ranked
interval - public units of measurements

Question 25

what does a small standard deviation mean ?

Answer 25

scores are close to the mean

Question 26

what does a large standard deviation mean ?

Answer 26

scored are far from the mean - lots of individual differences

Question 27

What are the steps for the wilcoxon test ?

Answer 27

1. calculate the difference between each pair of scores. if the difference is zero ignore it in ranking. 2. rank the differences from low to high ignoring negatives. 3. add up the ranks for positive differences. then for the negative differences. 4. chose the smallest value (observed value). 5. compare it to the critical value table and write the significance statement.

Question 28

in the wilcoxon test, does the observed value need to be lower or higher than the critical value ?

Answer 28

equal to or lower than.

Question 29

what data is used to calculate the chi squared test

Answer 29

nominal

Question 30

what is a positive skew

Answer 30

most of the scores are towards the left (lower than the mean)

Question 31

what is a negative skew

Answer 31

most of the scores are on the right (higher than the mean)

Question 32

how would you make estimates from data

Answer 32

* round the numbers * do the calculation

Question 33

how do you make order of magnitude calculations

Answer 33

* work out the apporximate value for all numbers (rounding the number) * see how many times bigger or smaller the number is

Question 34

what are non parametric tests

Answer 34

* inferential tests like binomial sign test, chi squared, wilcoxon, mann whitney U and spearmans Rho

Question 35

what are the steps for the Binomial sign test

Answer 35

* put a + if the number in the column A is bigger then the number in column B * put a - if the number in column A is smaller. * add up the pluses and minuses and select the smallest value for the observed value s

Question 36

what is the symbol for the observed value of the binomial sign test

Answer 36

s

Question 37

for the binomial sign test what must the observed value of s be for a significant result

Answer 37

s value must be equal to or less than the critical value

Question 38

when would you use the binomial sign test

Answer 38

* nominal, ordinal, interval data * repeated measures * difference

Question 39

when would you use the chi squared test

Answer 39

* nominal * independent measures * correlation

Question 40

when would you use the wilcoxon test

Answer 40

* ordinal, interval * repeated measures * difference

Question 41

when would you use the mann whitney u test

Answer 41

* ordinal, interval * independent measures * difference

Question 42

when would you use the spearmans rho test

Answer 42

* ordinal, interval * independent * correlation

Question 43

what are the steps of the mann whitney u test

Answer 43

* rank each column * add up the ranks for each column * choose the smallest value * calculate the smallest U equation which will be given in the exam (N1 = number of things in first column, N2 = number of things in second column)

Question 44

what is the symbol for the observed value in the mann whitney u test

Answer 44

u

Question 45

in the mann whitney u test when is the observed value of U significant

Answer 45

u value must be equal to or less than the critical value

Question 46

what are the steps for the Chi squared test

Answer 46

* calculate expected frequency = total rowx total column / overall total * find the observed value of x squared using the equation: sum of (E-O)squared divided by E * calculate the degrees of freedom = number of columns - 1 x number of rows -1

Question 47

for the chi squared test observed value to be significant what are the conditions

Answer 47

* observed value must be equal to or greater than the critical value

Question 48

what are the steps for the spearman's rho test

Answer 48

* rank each column * calculate the difference between the ranks * square this * add up the total * find the observed value of rho using 1-6 multiplied by the total divided by N(Nsquared -1)

Question 49

for the observed value of the spearmans rho test to be significant what are the conditions

Answer 49

observed value must be greater than or equal to the critical value

Question 50

how do you calculate expected frequency in chi2

Answer 50

row total x column total / overall total