Question

A common memory task is the classification of objects into categories. For example, a table is a piece of furniture; a dog is an animal, etc. This classification capability was used in a recent study of divided attention. Elderly adults were randomly selected from those answering a newspaper advertisement, and randomly assigned to two conditions: divided attention and no divided attention. Subjects in the "divided attention" group were told to memorize a list of 36 words while simultaneously listening to a tape recorder; subjects in a control group were told to memorize a list of 36 words and did not listen to a tape recorder. Subjects were then asked to classify the 36 words into 6 categories. (There were 6 words in each category.) The distributions of the correct number of recalled words / category were approximately normal in each of the groups, and a summary of the data for the words/category recalled are presented below: Recall of words/category

Treatment Samplesize Mean Standard deviation

Divided 31 1.75 0.70

Control 31 3.30 0.93

a) Is there evidence that the memory performance differs in the two groups? Test the appropriate hypothesis using α = .05.

b) One possible implication of this study is that high school students should not be dividing their attention by listening to music while studying. What results, if any, of this study would support the contention that students should not be dividing their attention?

Answer 1

Here we have to do the hypothesis test compairing two means

Let and be the population mean of words recalled by the divided and control group

Test statistic :