personal investigations

Core Aim of Investigation 1

To assess whether more screen time affects sleep quality in sixth form students.

Alternative Hypothesis of Investigation 1

There will be a significant correlation between average daily screen time and sleep quality in sixth form students, measured using the PSQI global score.

Directional hypothesis

There will be a significant correlation between average daily screen time, measured in hours over 7 days, and sleep quality, measured using the PSQI global score, in sixth form students.

Null Hypothesis of Investigation 1

There will be no significant correlation between average daily screen time, measured in hours over 7 days, and sleep quality, measured using the PSQI global score, in sixth form students. Any relationship found will be due to chance.

Covariable 1 of Investigation 1

Average daily screen time over 7 days.

Covariable 2 of Investigation 1

Sleep quality measured using the PSQI global score.

explain how covaraible 1 was operationalised

number of hours each participant spent on screens per day across 7 days, which was then averaged to produce one daily average screen time score for each participant.

explain how covaraible 2 was operationalised

Measured using the PSQI questionnaire out of 21; higher scores indicate poorer sleep.

Sample Method for Investigation 1

Opportunity sampling of sixth form students aged 16–18.

Why Opportunity Sampling?

It is quick, practical, and the students were easily available.

Procedure?

• recruited 6th form students- opportunity sampling

• Given info about study and informed students voluntary and could withdraw and responses confidential

• Participants tracked screen time for 7 consecutive days → used to calc average daily screen time in hours

• Completed PSQI questionnaire- 7 components e.g. sleep latency, duration and quality

• Scores paired together out of 21

• Scatter diagram created relationship between 2 covaraibles

• Spearman rank used to analyse data

Identify the graphical representation used.

• Scatter graph

Justify why this graphical representation was appropriate.

• study investigated a relationship between two co-variables, average daily screen time and PSQI score.

• A scatter diagram makes it possible to see whether there is a positive correlation, negative correlation or no correlation.

Identify the inferential statistical test used.

Spearman rank correlation coefficient

Justify why this inferential test was appropriate.

• study investigated a correlation between two co-variables, rather than a difference between conditions.

• The data was at least ordinal, as the PSQI scores can be ranked, and the screen time scores could also be ranked from lowest to highest.

 

Calculated Value for Investigation 1

rs = -0.019, indicating an extremely weak negative correlation (basically no relationship).

Is it significant

• No → any relationship found due to chance accept null hypothesis

Conclusion from Investigation 1

Screen time did not significantly affect sleep quality in the sample.

Strengths of Investigation 1

• Used standardized PSQI questionnaire

• practical and easy to conduct,

• addressed a real-life issue.

Weaknesses of Investigation 1

• Self-report bias,

• inability to establish cause and effect,

• extraneous variables (e.g., stress, caffeine).

One issue in validity and how dealt with it

• social desirability because participants may have underreported their screen time or made their sleep seem better than it really was.

• dealt with by making the responses anonymous/confidential → so Ps were more likely to give honest answers about their screen use and sleep quality.

   

   

another issue on validity and how to deal with

• demand characteristics, as Ps might guess that the study was investigating whether screen time harms sleep and then change their answers.

• This was dealt with by not revealing the exact hypothesis before data collection

• reducing the likelihood that participants would alter their responses to fit what they thought the researcher wanted.

Explain one way the validity of your study could be assessed.

• using concurrent validity by comparing the PSQI scores with another established sleep measure.

• If participants obtained similar sleep quality results on both measures, this would suggest the PSQI was a valid measure of sleep quality in this investigation.

Reliability

• test- retest reliability

• same 6th form students complete PSQI again

• After shirt period under similar conditions scores can be compared

• If scores similar on both → measure is consistent overtime

• PSQI is standardised

Ethical Issues

• Informed consent Ps needed to understand that they would be recording their screen time and completing a questionnaire about their sleep.

• dealt with by giving ps clear information before parcitipation, so they could make an informed decision about whether to take part.

another ethical issue

• confidentiality, as sleep habits and screen use are personal information.

• This was dealt with by ensuring that responses were anonymous,

• for example by using participant numbers rather than names.

 

Another ethical issue

• right to withdraw. Participants should not feel forced to continue once the study had started.

• This was dealt with by telling participants that they could leave the study or withdraw their data if they wished.

Ethical issue

• psychological discomfort, because some participants may have realised they had poor sleep quality once they completed the PSQI.

• This was minimised by making it clear that there were no right or wrong answers and by debriefing participants afterwards.

One Descriptive statistics used

• mean was an appropriate measure of central tendency because it uses all of the scores and provides an overall average for both screen time and PSQI score.

Figure for mean screen time and sleep quality

• Mean screen time = 7.62 hours

• Mean PSQI = 7.96

Strengths and wekanesses of mean

• A strength of using the mean as a measure of central tendency is that it uses all values in the data set, making it a sensitive measure.

• weakness is that the mean can be distorted by extreme values, such as the highest screen time score of 13.5 hours.

Another descriptive statisctics

The range was an appropriate measure of dispersion because it shows the spread of scores in a simple way, although it is less sensitive than standard deviation.

Strengths and weaknesses of range

• A strength of using the range is that it is quick and easy to calculate.

• For screen time, the range was 9.06 hours, and for PSQI the range was 13.

• However, the range is affected by outliers and only uses the highest and lowest values

• so it is less sensitive than standard deviation.