Answer:
The 80% confidence interval for the population mean is between 28.32 characters and 31.68 characters.
Step-by-step explanation:
We have the standard deviation for the population, so we can use the normal distribution. If we had the standard deviation for the sample, we would have to use the t-distribution.
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 the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 30 - 1.68 = 28.32 characters.
The upper end of the interval is the sample mean added to M. So it is 30 + 1.68 = 31.68 characters.
The 80% confidence interval for the population mean is between 28.32 characters and 31.68 characters.
If you mean by x over 4 that it is fraction then there is no different between it and divisions
x/4 = -120
x = -120 × 4 ( when division goes to the other side of equal it turns into multiplication)
x = -480
A. -480
According to given expression, we can say that the Triangles HZC and PEF are congruent, Therefore their corresponding sides will be equal.
that is :
and value of CH = 20 units
So, FP = CH = 20 units
hence, value of FP <u>can be </u><u>determined</u> .
Here is the solution:
-3x-42<span> > 3
Add the numbers
-3x > 45
Divide both sides of the inequation by -3 and flip the inequality sign.
x < -15
So the answer is: </span>x < -15
:)
5/30+4/6
5/30=1/6
1/6+4/6=5/6
5/6
Hope I helped!
