Support #1867
open
Significant change between waves - longitudinal weight
100%
Description
Hello,
I am comparing variable trcarfq across waves 8, 10 and 12. I have applied a longitudinal weight and have run my syntax in SPSS to output 95% confidence intervals. As I have applied a longitudinal weight, can I compare the data across these three waves based on the confidence intervals to determine whether the difference between years is significant? Or do I still need to calculate separately whether this difference is significant?
For example, 70% travel by car at least once a day in wave 8 and the lower and upper confidence intervals are 68% and 72%. 80% travel by car at least once a day in wave 10 and the lower and upper confidence intervals are 75% and 85%. Can I say that the % travelling by car once a day in wave 10 is statistically significantly higher than in wave 8 (because 75% is greater than 72%)?
Thank you.
Updated by Understanding Society User Support Team almost 2 years ago
- Category set to Weights
- Status changed from New to In Progress
- Assignee set to Olena Kaminska
- % Done changed from 0 to 10
- Private changed from Yes to No
Many thanks for your enquiry. The Understanding Society team is looking into it and we will get back to you as soon as we can.
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Understanding Society User Support Team
Updated by Olena Kaminska almost 2 years ago
Monica,
No, you can't compare as you describe because such comparison implies data from independent samples. In this situation the data comes from the same people, so this independence assumption is violated.
Best,
Olena
Updated by Understanding Society User Support Team almost 2 years ago
- Status changed from In Progress to Feedback
- % Done changed from 10 to 80
Updated by Understanding Society User Support Team about 1 year ago
- Status changed from Feedback to Resolved
- % Done changed from 80 to 100