Question

A researcher is interested in the effects of a new mnemonic strategy on short-term memory in 70 year-olds. She wants to include both those who are diagnosed as being in the mild stage of Alzheimer’s disease (AD) as well as 70 year-olds who have no diagnosable level of memory impairment. So, she will have 4 groups of 70 year-olds. One with no cognitive impairment that receives no intervention, one with no cognitive impairment that receives the training with the new mnemonic strategy, one group with individuals diagnosed with mild AD who receive no intervention, and the last group has individuals with mild AD who receive the training for the new mnemonic strategy.

Through a pretest of the participants’ short-term memory abilities, the researcher will insure that the basic abilities of the participants are equivalent within the non-AD groups and within the AD groups prior to the training. For 2 weeks, the mnemonic strategy participants will be asked to come to the university every other day for a 30-minute (computer based) training session (each session). Those not in the training groups will be asked to come in an do whatever they want on a computer for 30 minutes. Following the 2-week training period, all participants will be assessed using the Wechsler short-term memory scale, an established assessment of short-term memory abilities.

The project was reviewed and approved by the university’s Institutional Review Board. Although it is considered that no physical or psychological harm would come from the training strategy, all participants were required to receive clearance from their physicians in order to participate.

All participants will have their rights discussed with them and will only participate if they have signed the informed consent. For those who are unable to legally provide consent to participate, consent will be obtained from the legal guardian in addition to the informed assent of the participant.

All participants will be informed of the outcome of the study, and if the mnemonic training is shown to be beneficial, the training will be offered to all participants.

Identify the type of design. What are the strengths of this type of design? What are the weaknesses?

Answer 1

It is a 2x2 factorial design of two groups of 70 year old.

Group1: Without cognitive impairment, which is further divided into those without intervention and those with Mnemonic training

Group 2: With mild AD, which is further divided into those without intervention and those with Mnemonic training

Here the Independent variables are the 2 groups and the Mnemonic training. The controlled groups are those not receiving intervention and experimental group are those receiving Mnemonic training.

Factorial designs are most efficient for the experiments involve the study of the effects of two or more factors.It helps in finding the effect of one or more variable on a sample/groups. It not only gives the correlation but also the cause and effect.

The main disadvantage is that confounding factor can lead to error in the result.