Sorry to bother you guys again, I'm just having some real trouble trying to tackle this data.
The experiment I carried out was testing people's response to a oral glucose load when their bodies are in a fasting state and also to see if the person's BMI (body mass index) affected this response. To do this, I used the Oral Glucose Tolerance Test.
This test involved starving a bunch of volunteers overnight and giving them 50g of glucose in solution to be drank all at once. Measurements of their blood glucose concentration was just before the drink at 0 minutes and then 30, 60, 90 and 120 minutes after the drink. The plot of the group means are attached...
Rather than assess whether a person's BMI value has any effect on the value of their peak glucose, I thought it was more appropriate to test if BMI had any affect on the rate of increase and the rate of decrease in blood glucose.
Here is the processed data of: subject's BMI, rate of blood glucose increase (to peak), and the rate of blood glucose decrease (using glucose concentration 30 minutes after peak) <-- in this order.
I'm not exactly sure HOW to ask you what I want to assess but its something like this...
19.20 0.07222223 0.02666667
20.30 0.09333333 0.090000
21.30 0.2466667 0.040000
20.40 0.1416667 0.003333333
19.60 0.2766667 0.020000
18.44 0.2633333 0.05666667
23.22 0.3566667 0.150000
22.64 0.210000 0.060000
20.25 0.310000 0.010000
16.93 0.290000 0.01666667
24.60 0.2433333 0.050000
19.33 0.1766667 0.1133333
24.00 0.290000 0.02333333
What statistical test should I use to test whether BMI has an effect on a person's rate of increase AND decrease?
ie. if someone has a high BMI is it likely that their rate of increase will be very high and their rate of decrease (of blood glucose conc) will be slow?
Can I do this with a single test?