What’s the trade-off between certainty and confidence intervals?

1. Researchers often choose to reject the null hypothesis when there is less than a 5% likelihood of observing a given pattern in the data if the null hypothesis is true. They select 5% because
a. It’s a rule handed down by Isaac Newton
b. It’s the established scientific norm
c. It’s the absolute best way of establishing the truth

2. What’s the trade-off between certainty and confidence intervals?
a. If you want to be more certain of your estimate, your confidence interval will be smaller
b. If you want to be more certain of your estimate, there must not be a confidence interval
c. If you want to be more certain of your estimate, your confidence interval will be larger