Complete Question
A biologist reports a confidence interval of (3.5,4.9) when estimating the mean height (in centimeters) of a sample of seedlings. What is the estimated margin of error and the sample mean?
Answer:
The margin of error is 
The sample mean is 
Step-by-step explanation:
from the question we are told that
The upper limit is 
The lower limit is 
Generally the margin of error is mathematically represented as



Generally the sample mean is mathematically evaluated as

=> 
=> 
Answer:
Number of nickels = 5
Number of dimes = 10
Number of quarters = 8
Step-by-step explanation:
Fernando has a total of nickels + dimes + quarters = 3.25$
Let the number of nickels = x
Then x(.05) + dimes(.10) + quarters(0.25) = 3.25------(1)
He has twice as many dimes as nickels
dimes = 2×nickels
dimes = 2x--------(2)
He has 3 more quarters than nickels
quarters = nickels +3
quarters = x +3------(3)
From equations 1, 2, and 3.
x(.05) + 2x(.10) + (x + 3)(.25) = 3.25
.05x + 0.2x + 0.25x + .75 = 3.25
5x + 20x + 25x + 75 = 325
50x = 325 - 75
50x = 250
x = 5
Therefore the number of nickels are 5
from equation 2 number of dimes are 10
and from equation 3 number of quarters are 8.
Firstly , we will locate centres and radius in the figures
(a)
We can see that
centre=(h,k)=(0,0)
radius=r=5
now, we can use standard equation of circle

we can plug values
we get


(b)
We can see that
centre=(h,k)=(5,4)
radius=r=3
now, we can use standard equation of circle

we can plug values
we get


(c)
We can see that
centre=(h,k)=(4,3)
radius=r=5
now, we can use standard equation of circle

we can plug values
we get


Answer:
Step-by-step explanation: hope this helps!
Answer: 168 sq. in.
Step-by-step explanation: the shape is a cubiod the volume is lbh=3*7*8=168