Answer:
1) a. Move farther into the tails
2) a. Decreases
Step-by-step explanation:
Hello!
1)
Let's say for example that you are making a confidence interval for the mean, using the Z-distribution:
X[bar] ± *
Leaving all other terms constant, this are the Z-values for three different confidence levels:
90%
95%
99%
Semiamplitude of the interval is
d= *
Then if you increase the confidence level, the value of Z increases and so does the semiamplitude and amplitude of the interval:
↑d= ↑ *
They have a direct relationship.
So if you change α: 0.05 to α: 0.01, then the confidence level 1-α increases from 0.95 to 0.99, and the boundaries move farther into the tails.
2)
The significance level of a hypothesis test is the probability of committing a Type I error.
If you decrease the level from 5% to 1%, then logically, the probability decreases.
I hope this helps!