A quasi experiment on age and sleep Flashcards
What is the independent variable of this study?
Age of participants.
Two groups - young (16-18). Older (40-60)
What is the dependent variable of this study?
Average nightly sleep of each participant. Measured as the mean number of hours slept per night over 5 nights sunday-thursday.
Operationalized experimental hypothesis
There will be a difference in the amount of time young people sleep compared to older people as measured using the mean number of hours slept over 5 consecutive nights.
Is the experimental hypothesis directional or non-directional?
Non-directional.
Justify/explain why you chose to use a directional or non-directional hypothesis?
Although there is research suggesting that teenagers need more sleep than adults by ‘Crocetti et al’, actual research based on monitoring sleep patterns is conflicting, with some saying older people sleep more.
State an appropriate null hypothesis?
There will be no difference in the amount of time young people sleep compared to older people, as measured using the mean number of hours slept over 5 consecutive nights.
Identify the main characteristics of your sample group
Number: 33.
Gender: 20 females, 13 males.
Other significant features: 17 individual in young group, all between 16-18 and in the sixth form of our school. 16 individuals were in the older group, all 40-60 and related to participants in young group.
Sampling method you employed to select the sample
Volunteer/self selected.
How did you use the sampling method
Notice played in sixth form common room stating aims and procedures of quasi experiment. Explained how hours sleep would be measured over 5 nights. Volunteers responded by email and were given a chocolate bar and told data was confidential. Showed the posters to the older people.
Two advantages of your choice of sampling technique
- Less ethical issues because participants came to us knowing details of the study and understood their ethical rights from reading.
- Volunteer samples have a low dropout rate, since the keeping a diary of nightly sleep is both awkward and easy to forget, a volunteer sample from students and their family would be less likely to dropout.
Two limitations of your choice of sampling technique?
- Participants don’t represent everyone in society since the poster was put up in sixth form room, and so they’re probably academic so may affect sleep.
- Volunteer sample participants more likely to want to please and since the task of monitoring ones sleep is difficult they may be stressed but won’t withdraw.
Step by step description of procedures
- Volunteer sample was collected.
- Interviewed each participant. Guardian of young group present due to ethical need for proxy consent (easy because older group usually a parent).
- Ask the participants age then let them read the consent form.
- Emphasised that they need not participate and could walk away at any time. Asked to sign the form.
- Attached excel sheet to google classroom that each participant could put in data so no one was identified.
- 10 didn’t fill the form. No one contacted on email and emailed to thank them.
Appropriate descriptive statistic that could be used to describe the data collected?
- Mean as a measurement of central tendency.
- Standard deviation to see the spread of the mean numbers of hours slept.
Explain why your choice of descriptive is appropriate?
There were no extreme scores in the mean number, also the data was ratio therefore the mean and standard deviation were appropriate. The young group mean sleep score was slightly more than older group - 8.2 hours compared to 8.1h.
Identify an appropriate graphical representation that could be used to describe the data collected
A bar chart of means comparing the mean number of hours slept by the young group compared to older group was used to compare the data of young and older
Explain why your choice of graphical representation is appropriate?
A bar chart of the mean sleep time of both groups is a simple graphical method of visually showing if there is a difference between the two groups and which sleeps the most. Young group sleep score slightly higher.
Appropriate inferential statistic to display data
Mann Whitney U test
Why is your choice of inferential statistic appropriate?
We needed to find if there was a significant difference between the two different groups on how much time they slept asleep in hours, which is ratio data, that is data that’s at least ordinal
Briefly summarise your findings
Mann Whitney U score - 102.
N1=17, N2=16.
The critical value with a non-directional hypothesis when N1 is 17 and N2 is 16 at probability 0.05 is 81. So as our score of 102 is larger than this critical value we must accept null hypothesis.
What conclusions can you draw from these findings?
as our score of 102 is larger than this critical value we must accept null hypothesis, so this shows that age has no significant effect on the number of hours we sleep.
