Answer:
We need at least 217 compact fluorescent light bulbs
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
So it is z with a pvalue of 
, so 
Now, find M as such
In which 
is the standard deviation of the population and n is the size of the sample.
How many compact fluorescent light bulbs need to be selected?
We need at least n bulbs, in which n is found when 
So
We need at least 217 compact fluorescent light bulbs
Answer: Melanie swam 63 minutes more in second week.
Step-by-step explanation:
Given , Time taken by Melanie in first week to swim = 142 minutes
Combined time taken by her in first two weeks in swimming = 347 minutes
Now , time taken by her in second week = (Combined time of first two week) - (Time taken in first week)
= 347-142 minutes
= 205 minutes
Clearly , 205 > 142 i.e. She swam more in second week than first week./
Difference i= 205-142 = 63
Therefore, Melanie swam 63 minutes more in second week.
Answer:
The perimeter is 8 units
Step-by-step explanation:
The vertices of the given rectangle are: A(-6,-4) B(-4, -4), C(-4, -2), and D(-6,-2)
We use the absolute value method to find the length around the edges of the rectangle.
|AB|=|-6--4|=|-2|=2
|BC|=|-4--2|=|-2|=2
The perimeter of the rectangle is
P=2(w+l)
Substitute the dimensions to get:
P=2(2+2)
P=2(4)
P=8 units.
The perimeter is 8 units.
Answer:
1 1/12
Step-by-step explanation:
You take 2 3/4 and subtract it by 1 2/3
Make them into improper fractions 11/4 - 5/3
you multiply 11/4 by 3 and 5/3 by 4 to get a common denominator
you get 33/12 - 20/12 and get 13/12
then make it a mixed number
hope this helps :)
