WEEK 1 - introduction, data and experiments

why should data be summarised?

- Large sets of numbers are hard to learn from

- We need to take steps to simplify and summarise the number into something more digestible

- A good start is simply to count how often each number occurs

what is the x axis split into on a histogram?

bins

what does a histogram look like for continuous data?

The x axis is split into bins

Each bin covers a set range

Here the bins have a width of 2

what do histograms visualise?

the distribution of a data set

what does increasing the number of bins on a histogram do?

gives it more resolution

BUT

can make the distribution noisier as well (especially with a small number of samples)

what are the shape of histograms described by?

mean

variance

skewness

kurtosis

what is the mean in terms of histograms?

the mean is the average value of the data, representing the balance point of the distribution along the x-axis

what is variance in terms of histograms?

variance measures how spread out the data is—how far the bars (data values) are, on average, from the mean.

what is skewness in terms of histograms?

skewness describes the asymmetry of the distribution—whether the data has a longer tail to the right (positive skew) or to the left (negative skew).

what is kurtosis in terms of histograms?

kurtosis describes how peaked or flat the distribution is, and how heavy the tails are compared to a normal distribution

what are the types of distribution that reflect the differences in the underlying data set?

Normal (Gaussian): Symmetric, bell-shaped

Uniform: Data evenly spread

Skewed: Asymmetric (left-skewed or right-skewed)

Bimodal: Two peaks

Multimodal: More than two peaks

what is normal distribution?

a normal distribution appears as a symmetric, bell-shaped pattern, with the tallest bars in the center (around the mean) and bars decreasing evenly on both sides

what is uniform distribuion?

a uniform distribution appears flat, with all bars having roughly the same height, meaning the data is evenly spread across the range

what is skewed distribution?

a skewed distribution is asymmetric, with most data on one side and a long tail on the other—right-skewed if the tail is to the right, left-skewed if the tail is to the left

what is bimodal distribution?

a bimodal distribution has two distinct peaks (modes), indicating two common values or groups in the data

what is multimodal distribution?

a multimodal distribution has more than two peaks, showing multiple frequent values or clusters in the data set

where is the data point added?

to its corresponding value

where is each data point in the data set added?

to its bins until the whole data set is displayed

- can gradually see the shape of the distribution as more data comes in

what is research methods B?

Transferrable skills

Building a toolkit for psychological research

Can be applied to other modules

what are the practical aspects of research?

what is jamovi?

Intuitive graphical interface for analysis

Straightforward to create and tune analysis

what are the limitations of using jamovi?

Not very reproducible - hard for others to know what you did

Time consuming - if you want to repeat an analysis you need to click through all the buttons again from scratch

what is R?

Reproducible analysis scripts

what are the strengths of R?

Highly transparent - very clear what steps were taken in which order

Collaborative- can send and share reproducible analyses to colleagues

Efficient - can rerun analyses on new data very quickly once the script has been written

what are the limitations of using R?

A bit harder to set up

what are the Practical data analysis skills that will be gained from this module?

Pre-registration

How to read and write methods sections

How to read and write results sections

what is the research project?

Design your own experiment around a replication of a classic, but very outdated, psychology study

Design and experiment and collect data in groups

Write a pre-registration report and a full practical report based on your study

what is the quote from THE FEMALE BRAIN that supports the idea that society is full of 'folk wisdom'?

"A woman uses about 20,000 words per day while a man uses around 7000"

what did Mehl et al (2007) show?

hat women use an average of 16,215 words per day and men use an average of 15,669 words

what is a dataset?

A collection of data acquired for specific purpose

May relate to multiple experiments or hypotheses

what is a variable?

A number that can 'vary' (take a high or low value) depending on an attribute that we're trying to measure

We typically measure several variables from each participant

These typically form one collum in a data file

what is a nominal variable?

No relationship between different possibilities in scale - sometimes called categorical data

what is an ordinal variable?

A natural order between possibilities but nothing else

Can't interpret the magnitude of differences

what is an interval variable?

The possibilities are ordered and have interpretable magnitudes through 0 does not have a special meaning

what is a ratio variable?

Like interval data

But now 0 is directly interpretable and we can interpret ratios between values

what is a continuous variable

A variable that can charge freely to take any value  

For example – temperature could be 4C, 10.34C or –00.45C  

what is a discreet variable?

A numbered variable that takes one of a fixed set of values

For example - number of cars owned

what variables are continuous and which are discreet?

what are latent and observable variables?

We cannot see directly many of the things we are interested in in psychology

Latent variables are variables that can only be inferred indirectly through a model from other observable variables that can be directly observed or measured

We must take care when research involves latent variables

- What has actually been measured?

- Is this observed variable a good proxy?

We often must use observable factors as a proxy for important latent variables, but it can be difficult to do this well.

It might be that the 'best' observed variable depends on practicalities and the desired outcome of the project

what is quality of life?

Quality of life is a 'latent' variable that is inferred from observed variables that we can directly measure eg health, financial stability, social support etc.