Given:
Sample mean = 65.4
Standard deviation = 1.2
Sample size = 45
Confidence level = 99%
To find:
The confidence interval.
Solution:
The formula for confidence interval is
where, is sample mean, z* is confidence value, s is standard deviation and n is sample size.
Confidence value or z-value at 99% = 2.58
Putting the given in the above formula, we get
Therefore, the correct option is D.
Answer:
Step-by-step explanation:
we know that
The area of the shaded region is equal to the area of the sector minus the area of the triangle
step 1
Find the area of the circle
the area of the circle is equal to
we have
substitute
step 2
Find the area of the sector
we know that
The area of the circle subtends a central angle of 360 degrees
so
by proportion find out the area of a sector by a central angle of 72 degrees
step 3
Find the area of triangle
The area of the triangle is equal to
step 4
Find the area of the shaded region
Subtract the area of the triangle from the area of the sector
