# 'Before you begin' quiz (Year 1 recap) Flashcards

What is the purpose of the ‘control’ condition?

To allow psychologists to make inferences about a cause.

What is a t- statistic?

The ratio of systematic : unsystematic variation

What is standard deviation?

The measure of dispersion of scores around the mean.

What does a small standard deviation represent?

All data points are close to the mean, therefore the mean is a ‘good fit’ of the data.

What does a large standard deviation represent?

All data points are very spread around the mean, therefore the mean is not a ‘good fit’ of the data.

What does a significant test statistic tell us?

The test statistic is larger than we would expect if there was no effect in population.

What does a positive correlation represent?

As one variable increases, the other increases too.

What does a negative correlation represent?

As one variable increases, the other decreases.

What is a Type-1 error?

We conclude there is an effect when in fact there is not.

What is a Type-2 error?

We conclude there is not an effect when in fact there is.

What is standard error?

- The standard deviation of sample means.
- Measure of how representative samples parameters are of the population.
- Computed from known sample stats.
- Provides an unbiased estimate of standard deviation.

Interpreting SPSS: What do we do if the Levene’s test is significant?

Read data from the ‘equal variances not assumed’ row.

What does positively skewed data look like on a graph?

Frequent scores clustered towards the lower end of the graph.

What does negatively skewed data look like on a graph?

Frequent scores clustered towards the higher end of the graph.

What does normally distributed data look like on a graph?

A bell curve.