I am conducting a systematic review for which I can only use results from independent samples. Now, I have 5 independent samples (A, B, C, D, E) from 4 studies. I know that samples A and B do not overlap, nor do samples D and E. Is there a way to deduce how many independent samples I have in total?

Below the number of subjects in each sample:

A: N = 20

B: N = 59

C: N = 50

D: N = 39

E: N = 40

Any help is much appreciated! ]]>

For DV: placement (in sight or out of sight) and sticker presence (yes/no) I used a binary logistic regression.

For DV: Usage I do have some problems finding the right test.

I would like to test Usage in 2 ways: between the no sticker and sticker group. and within with these 2 questions from the survey with the normally as a baseline.

Hypothesis:

Students, who are exposed to an informational warning sticker including a solution and visual element on their desk, are more likely to lower their mobile phone usage while studying than when there is no sticker.

Furthermore I do have some moderators which possibly could have an influence on the effect of the sticker on usage.

In the attachment you can find the conceptual model.

Is there someone who can help me or explain me which test to use?

How often did you check your mobile phone while studying today?

Every minute

Every 5 minutes (12x an hour)

Every 10 minutes (6x an hour)

Every 15 minutes (4x an hour)

Every 20 minutes (3x an hour)

Every 30 minutes (2x an hour)

Less than once in an hour

Did not check my phone

How often do you normally check your phone while studying?

Every minute

Every 5 minutes (12x an hour)

Every 10 minutes (6x an hour)

Every 15 minutes (4x an hour)

Every 20 minutes (3x an hour)

Every 30 minutes (2x an hour)

Less than once in an hour

Do not check my phone while studying

COLOUR:

Red: £14,000

Blue: £12,000

ENGINE SIZE:

1.5 litre: £12,000

2 litre: £16,000

MANUFACTURER:

Toyota: £15,000

Honda: £13,000

Question) If I was to buy a red 1.5 litre Honda, how much would I expect to pay?

I think it's a trick question but at the same time intuitively I know it's less than £14,000 and more than £12,000 - but how can we answer this question properly? (i.e. using maths!) ]]>