Personal Investigation 2 - Sleep And Age

Question 1

State the operationalised co-variables in PI.1

Answer 1

Age (16-24 and 25+) and Pittsburgh sleep quality index (PSQI) scores

Question 2

State an operationalised alternate hypothesis for PI.2

Answer 2

There will be an increase in PSQI scores in adolescent participants aged 16-24 compared to adult participants aged 25+.

Question 3

Identify if the alternate hypothesis for PI.2 is directional or non-direction, and justify the reason.

Answer 3

Directional - because there is already previous research to suggest a particular outcome

Question 4

State an appropriate null hypothesis for PI.1

Answer 4

There will be no significant difference in PSQI scores in adolescents compared to adults, and any difference will be due to chance.

Question 5

Identify main characteristics of the sample group for PI.2 and the sampling method used.

Answer 5

20 participants, 10 aged 16-24 and 10 aged 25+. Opportunity sampling

Question 6

Identify and justify the experimental design used in PI.2

Answer 6

Quasi experiment (independent groups), as age is naturally occurring and cannot be manipulated

Question 7

Justify using the mean and SD for both co-variables in PI.2

Answer 7

Both sleep and age have a true zero, making it ratio data meaning the mean can be calculated, and therefore the SD

Question 8

Identify and justify an appropriate graphical representation to describe the data collected in PI.2

Answer 8

Bar chart - since it can display mean scores of both age categories

Question 9

Identify and justify an appropriate inferential statistics test for PI.2

Answer 9

Mann-Whitney U - since the research explores the difference in PSQI scores between adolescents and adults
Independent design was used
And level of measurement is ratio

Question 10

Summarise the findings and significance linked to variables

Answer 10

Mean for 16-24: 8.4,
Mean for 25+: 7.6
SD for 16-24: 9.8
SD for 25+: 5.9

Calculated U value: 33
Critical value: 27

Question 11

Considering the calculated U value and the critical value, what conclusions should be drawn?

Answer 11

Since the calculated U value (33) is HIGHER than the critical value (27), findings are NOT significant and therefore the null hypothesis should be accepted.

Question 12

Identify issues of reliability in PI.1

Answer 12

Non-standardised procedures in the pilot

Question 13

Identify issues of validity in PI.2

Answer 13

Social desirability bias on the sleep task

Question 14

Identify ethical issues in PI.2

Answer 14

Invasion of privacy and confidentiality