Hypotheses & Aims

An aim = A general statement about the purpose of the investigation whereas the hypothesis is much more specific and tells us what the study is designed to test. “To see…..”

A hypothesis…. A prediction of what will happen in a given situation It’s a precise testable statement about the expected outcome of an investigation

Null hypothesis – states there will be no difference in conditions, no effect of the IV on the DV, no relationship The alternative hypothesis (alternative to the null) is a prediction that there will be a difference/ an effect/ a relationship If it’s an experiment, this can also be called the experimental hypothesis

An example to work through Baddeley predicts that the digit span (amount of numbers stored) of STM can be increased if the digits are read out loud rather than read subvocally (in your head). How would we set this up as an experiment? What is the IV, and the DV? Now, let’s make up the hypotheses

HypothesisDefinitionExample One – tailed Directional More precise than non-directional as it predicts the direction and nature of the effect. Uses words like higher, lower, more, less, increased etc This is used if….. Pts who read digits out loud will later recall a greater no. of digits than pts who read the digits subvocally.

HypothesisDefinition Example Two – tailed Non- directional The direction/nature of the effect is not specified This predicts an effect, a relationship, a difference in conditions Used if……….. The (IV) will have an effect on the (DV) The method of reading the digits will have an effect on the no. of digits recalled. OR There will be a difference in the no. of digits recalled in the reading outloud condition compared to the subvocal condition

HypothesisDefinition Example NULL There will be no effect, no difference, no relationship Used as it makes a very precise prediction that can be disproved, thus supporting the alternative hypothesis Just turn the non- directional hypothesis into the null So The (IV) will have NO effect on the (DV) Or There will be NO difference in…….

If an experiment, phrase your hypothesis in terms of the IV/DV or the conditions of the experiment If it’s a correlation (seeing if there is a relationship between two variables) then express the hypothesis in terms of a correlation e.g. positive or negative correlation a correlation no correlation between…..