28 is 140% of 20
Hope this helps!
Answer:
(B) (0.396, 1.712)
Step-by-step explanation:
From the information given;
Confidence Interval = 0.95
Significance Level 
The confidence interval for regression coefficient beta (whereby in this case it is the coefficient of the diameter) is expressed by:
= 
From the regression coefficient, the estimated value of beta^ = 1.054


B. Total number of times the activity is performed: Number of times an event occurs
Answer: Test statistic = -8 and rejected region is (-∞,-1.966) and (1.966, ∞)
Step-by-step explanation:
Since we have given that
X is the length of a rod.
Sample Mean = 2 inches
Standard deviation = 0.5 inches
n = 400
Hypothesis are

Test statistics would be

Degrees of freedom = n-1 =400-1 =39
and 
Using the t-distribution table, we get that critical value z = 1.966
Since the two tail test will be applied to this,
So, the acceptance region will be (-1.966, 1.966)
Hence, the rejected region will be (-∞,-1.966) and (1.966, ∞)
1.

so

Answers B and D.
2.

Answer D.
3.
The same as point 2. Answer D.
4.
Answer C.