Answer:
2.51 < σ < 3.92
Step-by-step explanation:
We will use Chi-Square distribution to create the interval. We have the following information:
n = 41
Level of Confidence : 95%,
This corresponds to Chi-Square values of:
24.433 for the left tail and 59.342 for the right tail
We need to calculate the sample Variance. This is done on attached photo 1 (the shortcut formula for finding variance was used)
We get s = 9.3866.
See the construction of the confidence interval on the second attached photo
1 Year: 19
2 Years: 9.50
3 Years: 4.75
4 Years: 2.38 (2.375, but rounded)
The meaning of vertical angles are two congruent angles formed by the intersection of two straight lines.
On this question is given that angles one and two are vertical, and the measure of one of them or angle two is 31 degrees.
As said before vertical angles are congruent, or have the same measurement.
Meaning that angle one is equal to 31 degrees.