week 5

Question 1

Why do we use statistics

Answer 1

As real data is very messy as there is data for different conditions and different groups

Question 2

what are measures of central tendency’s

Answer 2

the middle point of a frequency
we cannot draw any inferences or generalisations

Question 3

types of measures of central tendency’s

Answer 3

the mean
the median
the mode

Question 4

what is the weakest and strongest type of data

Answer 4

weakest: categorical: nominal then ordinal
Strongest: continuous: interval then ratio

Question 5

What types of central tendency can be used with certain types of data

Answer 5

Nominal only mode
ordinal: median, ordinal
Interval: mean, median and mode
Ratio: mean, median and mode

Question 6

What is mean

Answer 6

most commonly used
symbol is ether an x or m
uses all the data set

Question 7

How do you calculate mean

Answer 7

Add up all the values/scores and divide by the number of values /score

Question 8

What is the median

Answer 8

it is simply the middle value

Question 9

How do we calculate the median

Answer 9

Odd number: place the data in order from lowest to highest, follow the equation above, take the total number of participants and ass 1, then divide this value by 2, this gives us our median position

Even data set: place even data in order, use the same equation calculate the middle position of data set. Take the the value for the position before and after and then add them up and divide them by 2

Question 10

What is the mode

Answer 10

the value which appears most frequently in the data set
Bimodal- have two modes
Multimodal- have more than two modes

Question 11

What is measure of dispersion

Answer 11

how much the data vary

Question 12

What are the types of measure of dispersion

Answer 12

the range
minima and maxima
variance
standard deviation
only calculated on continuous data

Question 13

What is minima and maxima

Answer 13

minima is lowest values in the data maximum is the highest value

Question 14

What is the range

Answer 14

the highest value in the data set minus the lowest and then add one

Question 15

What is variance

Answer 15

amount of spread
calculated by examining the degree to which a persons score/ data point differs from the group mean
Calculated by identifying how each sore deviates form the mean

Question 16

What is the equation for variance

Answer 16

S2= the sum of the difference squared/ number of participants-1

Question 17

What is the steps of calculating variance

Answer 17

calculated the mean
calculate the amount each score varies form the mean
add up all the differences-this value is then used in the equation
complete the equation

Question 18

What is standard deviation

Answer 18

tells you how well the mean represents the data
When reporting a mean you should also report the standard deviation

Question 19

What is the equation to calculate standard deviation

Answer 19

Sd= the square root: the sum of the difference squared/number of participants-1

Question 20

What is normal distribution

Answer 20

Referred to as the bell curve
the mean, median and mode are all the same
68% probability of selecting a score between +1 and -1
95% probability of selecting a score between +2 and -2

Question 21

What is confidence intervals

Answer 21

typically you’ll see 95% confidence intervals

Question 22

How to calculating confidence intervals

Answer 22

take the standard error and multiply this by 1.96
Add this to the mean to calculate the upper CI
subtract this from the mean to calculate the lower CI

Question 23

What is standard error

Answer 23

Quantifies the variability between samples drawn from the same population. It assesses how far a sample statistic likely falls from a population

Question 24

What is skew

Answer 24

positive- scores go towards the lower scores
Negative- scores go towards the higher scores
Data is skew if value is above 1 or -1

Question 25

What is Kurtosis

Answer 25

describes the pointyness of a distribution
when the distribution is flat and short it is platykurtic
when the distribution is thin and tall it is leptokurtic