Adjusting assertion threshold to fix flaky test

[crawlingcub]

Hi,

I observed that the test test_calc_bootstrap sometimes fails when the seed setting line such as np .random_seed(123) is removed. It failed 55 times out of 500 times that i ran. I adjusted the assertions in the test to make sure that they always pass. Please let me know if this change looks reasonable. Since the test is more stable, do you think I can also remove the seed-setting line?

Happy to include any other suggestions.