Statistics Paper 2

Question 1

What is nominal data?

Answer 1

Categorised data with no ranking/order. Each value will have a name or label

Example: Gender, colours

Question 2

What are strengths and weaknesses of nominal data?

Answer 2

S- Simplistic and easy to collect/organise as it involves basic categorisation
W- Does not provide any order and limits the types of statistical analyses that can be performed

Question 3

What is ordinal data?

Answer 3

Data that is presented in rank order but does not specify the size of differences between ranks

Question 4

What are strengths and weaknesses of ordinal data?

Answer 4

S- Provides order information
W- No quantitative differences so doesn’t indicate differences between ranks

Question 5

What is interval/ratio data?

Answer 5

Quantitative measues of difference on a numerical scale
Interval: equal intervals, has no true zero point
Ratio: all properties of interval data with a true zero
Examples of interval- temperature
Examples of ratio-weight, height

Question 6

What are strengths and weaknesses of interval/ratio data?

Answer 6

S-Rich statistic analysis
W-Assumption of equal intervals, which may be inaccurate

Question 7

What are measures of central tendency?

Answer 7

General term for all calculations in quantitative data to find the mean, median and mode to discover patterns in data

Question 8

What is the mean, mode and median?

Answer 8

Mean- the average
Mode-appears most often
Median- in the middle when all values are listed in order

Question 9

What are strengths and weaknesses of using the mean?

Answer 9

S- Easy to calculated, includes all values
W- Infuenced by outliers

Question 10

What are strengths and weaknesses of using the median?

Answer 10

S-Easily identifiable and less effected by outliers
W- May have lots of numbers to order so is time consuming. Not representative of all values

Question 11

What are strengths and weaknesses of using the mode?

Answer 11

S- Easy to calculate
W- There may be multiple modes

Question 12

What is a normal distribution?

Answer 12

Symmetrical, bell-shaped distribution where most of the data points cluster around the mean. The mean, median and mode are located at the centre and are equal.

Question 13

What is a positively skewed distribution?

Answer 13

Asymmetrical, concentrated on the left. The mean is greater than the median, which is greater than the mode

Question 14

What is a negatively skewed distribution?

Answer 14

Asymmetrical, concentrated on the right. The mean is less than the median, which is less than the mode

Question 15

What are measures of dispersion?

Answer 15

General term for any measure of a spread of data

Question 16

What is the range and what are its strength/weaknesses?

Answer 16

Range- Subtract lowest from highest +1
S- Useful for a quick, basic measure
W- Data may look misleading if there is an anomoly

Question 17

What is standard deviation and what are its strength/weaknesses?

Answer 17

SD- How much each score deviates from the mean. The larger the sd, the greater the spread
S- Accurate idea of distribution, representative of groups variation, useful for comparing variability

Question 18

What are inferential statistics?

Answer 18

Determining whether results are due to chance. The sign test, probability and significance, type I/II errors

Question 19

What significance level do pyschologists commonly use and why?

Answer 19

p<0.05 because it is used when high levels of significance are not needed and allows for the null hypothesis to be 5% or more true to be accepted. The stringent level is 1% used for levels of high confidence like in medical scenarios.

Question 20

What is a parametric test?

Answer 20

Making assumptions about the data’s underlying distribution assuming a normal distribution. Assumptions include: distribution, equal variances and data is interval/ratio

Question 21

What are the strengths and weaknesses of a parametric test?

Answer 21

S- More powerful than non-parametric when assumptions are met, allows for more detailed inferences about population parameters
W- Not suitable when data does not meet assumptions

Question 22

What is a non-parametric test?

Answer 22

Making fewer assumptions about the data’s distribution, can be used with ordinal data.
Assumptions: few or none/ordinal data

Question 23

What are the strengths and weaknesses of a non-parametric test?

Answer 23

S- More flexible with fewer assumptions about the data
W- Less powerful than parametric tests, limited in the detail they can provide about population parameters

Question 24

What is the saying for the statistical tests?

Answer 24

Carrots Should Come
Mashes With Suede
Under Roast Potatoes

Question 25

What do each of the acronyms in the statistical test mean?

Answer 25

Chi^2, Sign Test, Chi^2 Mann Whitney U, Wilcoxon Test, Spearmans Rho Unrelated t-test, Related t-test, Pearsons Product Moment

Question 26

What are each of the factors it could fit into?

Answer 26

Nominal, ordinal or interval data Difference or correlational If difference, independent or repeated measures?

Question 27

What are the steps to finding the critical value/calculated value in significance?

Answer 27

-Compare test statistic to critical value -Look at significance levels -Degrees of freedom/ sample size

Question 28

What is the rule for significance in stats?

Answer 28

If the test has an R in it, the calculated value has to be equal or greateRR than the critical value

Question 29

How do you write significance statements?

Answer 29

1. State whether the calculated value is less or more than the critical value 2.State whether the results are significant 3.State whether the null is accepted or rejected 4.Write out the relevant hypothesis 5. Report the figures in brackets- calculated, critical value, number of participants, report if p was less or more than 0.05, one or two tailed

Question 30

What is a type I error?

Answer 30

False positive- The null hypothesis is rejected when it should be accepted

Question 31

What is a type II error?

Answer 31

False negative- The null hypothesis is accepted when it should be rejected

Question 32

How do you complete the sign test?

Answer 32

1) Convert results to nominal data, add + or - signs on the right 2)Add the + and - up 3) Use the smallest number 4)Look at if it is a one or two tailed study and how many participants there are- correlate this on the critical value chart 5)Find the number- if its less or equal to the calculated value, it is significant