A report on the difference in the measurements by two evaluators of the cardiac output of 20 patients using Doppler echocardiography was done. Both observers took measurements from the same patients. The measured outcomes are shown in the accompanying table. Conduct a hypothesis test to determine if the average cardiac outputs measured by the two evaluators differ. Use a significance level of 0.02. Assume the population variances to be equal.

H0: d=0

HA: d0

Patient Evaluator_1 Evaluator_2

1 5.3 5.7

2 5.3 6.4

3 5.7 7.1

4 5.7 6.5

5 5.8 6.1

6 6.3 6.4

7 6.4 7

8 6.5 7.7

9 6.7 7

10 7.8 8.3

11 8.3 8.1

12 8.3 8.4

13 9.9 11.2

14 10.4 10.1

15 10.5 11.3

16 10.6 11.5

17 10.7 11

18 10.8 11

19 10.9 11.2

20 11.4 11.7

Calculate the test statistic

t =

(round to 2 decimal places)