C RM- Descriptive Statistics, Presentation of quantitative data and Distributions

Question 1

what are measures of central tendency?

Answer 1

analyses how close scores are to the average participant response

Question 2

what are the three types of average

Answer 2

mean
mode
median

Question 3

what is the mean?

Answer 3

the average, calculated by adding all data scores together, then dividing the total by the actual number of scores

Question 4

what type of data does the mean use?

Answer 4

interval/ ratio

Question 5

strengths of using the mean

Answer 5

-accurate and sensitive as all scores are taken into consideration, therefore is highly representative
-can be used to calculate standard deviation

Question 6

weaknesses of using the mean

Answer 6

-can be skewed by an anomalous score, making the score unrepresentative of the raw data set
-may not always be an actual score or whole number- not an entirely accurate reflection

Question 7

what is the median?

Answer 7

the middle score or value that is found with data in an ordered list

Question 8

what type of data does the median use?

Answer 8

ordinal data or higher

Question 9

strengths of using the median

Answer 9

-unaffected by extreme scores as only the middle number is used, higher accuracy and representation of the central tendency

Question 10

weaknesses of using the median

Answer 10

-may not be an actual score (even number)- limited in how representative it is
-not always appropriate to use e.g. small data sets with large differences (1,2,1000,1001 = 501)

Question 11

what is the mode?

Answer 11

the most common or frequent score

Question 12

what does bi-modal mean?

Answer 12

the two most common scores

Question 13

what does multi-modal mean?

Answer 13

three or more scores that are the most common

Question 14

what type of data does the mode use?

Answer 14

nominal

Question 15

strengths of using the mode

Answer 15

-unaffected by extreme, anomalous scores, giving a more accurate reflection
-always an actual score, accurate representation of central tendency

Question 16

weaknesses of using the mode

Answer 16

-not all data sets will have a mode, so limited in its usefulness
-doesn’t take into account all data, only most frequent- inaccurate

Question 17

what are the two ways we measure dispersion?

Answer 17

range and standard deviation

Question 18

what are measures of dispersion?

Answer 18

they are used to understand how spread out scores are from the average participant response

Question 19

what does a large dispersion indicate?

Answer 19

individual differences are present and/or poor experimental control (inconsistencies in the data)
-the larger the SD of a set of scores, the larger the variation and more spread out they are relative to the mean

Question 20

what data does standard deviation use?

Answer 20

interval/ ratio data

Question 21

what does standard deviation indicate?

Answer 21

the average of the distances of all scores around the mean
-measuring how much individual scores deviate from the mean in a single number

Question 22

strengths of using standard deviation

Answer 22

-higher validity as all values are taken into account, giving a more accurate representation of data distribution
-allows for interpretation of individual scores (how far they are from the mean)

Question 23

weaknesses of using standard deviation

Answer 23

-complex to compute and difficult to understand, not quick or easy to calculate
-less meaningful if data is not normally distributed

Question 24

what data does the range use?

Answer 24

ordinal

Question 25

what is the range?

Answer 25

the difference between the highest and lowest score in a set of data

Question 26

how is the range calculated?

Answer 26

by subtracting the lowest score form the highest score

Question 27

strengths of using the range

Answer 27

-easy and simple to calculate -includes extreme values

Question 28

weaknesses of using the range

Answer 28

-ignores most of the data, focuses on two most extreme scores, so lots of individual data is ignored -easily distorted by extreme values

Question 29

what are percentages?

Answer 29

a number out of 100 -fractions can be converted to a percentage e.g. 5/100 = 5%

Question 30

what are correlations?

Answer 30

coefficients between -1 and 1

Question 31

what is a +1 coefficient called?

Answer 31

perfect positive correlation

Question 32

what is a -1 coefficient called?

Answer 32

perfect negative correlation

Question 33

what is a 0 coefficient called?

Answer 33

zero correlation

Question 34

positive correlation

Answer 34

two variables move in the same direction

Question 35

negative correlation

Answer 35

one variable decreases, one variable increases

Question 36

zero correlation

Answer 36

there is no linear relationship between the two variables

Question 37

what are graphs used for?

Answer 37

to display/ present data in a form which is easy to read

Question 38

bar charts

Answer 38

-used for differences between groups or categories -data is nominal (labels are discrete and categorical) -compares multiple groups of data on anything -good for comparing averages and modes

Question 39

scatter graphs

Answer 39

-correlational data -shows a relationship between two variables -data is ordinal or interval -includes a labelled axis and title

Question 40

histograms

Answer 40

-interval data only -used for continuous data, scores are placed alone the x axis and frequency along the y axis -no space between the bars

Question 41

pie charts

Answer 41

-good for showing nominal results in a target population -shows the frequency of categories- sections are colour coded

Question 42

what variable does the x axis often have in an experiment?

Answer 42

the independent variable

Question 43

what variable does the y axis often have in an experiment?

Answer 43

the dependent variable

Question 44

what is a correlation coefficient?

Answer 44

a number between -1 and 1 that measures the strength of a linear association between two variables 0= no association >0= positive association <0= negative association

Question 45

what is normal distribution?

Answer 45

a probability distribution that is symmetric about the mean , showing that data near the mean are more frequent in occurrence than data far from the mean