I have to compare two fitnesstrackers: W1 and W2 and select the most accurate one, the most performant one in measuring HeartRate data.

For that, I measured for each of my 10 participants their heartrate using: an Electrocardiogramm (ECG), W1 and W2.

Now for each of my participants, I have 4 same size column data (the time of the data, the ECG data, W1 and W2 data).

The ECG data are for me the reference: those data are the 'true' ones. I want to compare W1 data and W2 data with my ECG data and select the one that is the most accurate in measuring Heartrate.

What I did:

for each of my participant, I have more than a 100 points

- I did a nomality test to each of my intsrument and they all follow a normal distribution.

- I calculate the RMSE, the variance and the mean between ECG and W1/W2. But I don't know what or how to conclude.

I tried actually a lot of statistical test, and I don't know what to conclude or which one I should choose:

- should I use linear regression between ECG and W1/2? I think linear regression is more a prediction statistical test, and i don't think I should use it. I ploted the scatter plot and it doesn't look very linear.

- A student test (or t-test?). It's a comparaison test and I also don't know how to conclude with my result: I have 2 independant variables (ECG and W1 or ECG and W2) that follow a normal distribution with not equal variances.

- Should I use some kind of equilavence test? because I want to see which one (W1 or W2) is more 'equivalent' to ECG? but which one?

- I saw some ANOVA method but I don't know if I should use it and how...

I'm a bit lost...