Answer:
A sample of 179 is needed.
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
.
That is z with a pvalue of
, so Z = 1.44.
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.
A previous study found that for an average family the variance is 1.69 gallon?
This means that 
If they are using a 85% level of confidence, how large of a sample is required to estimate the mean usage of water?
A sample of n is needed, and n is found for M = 0.14. So






Rounding up
A sample of 179 is needed.
Answer:
- an = 3(-2)^(n-1)
- 3, -6, 12, -24, 48
Step-by-step explanation:
These variable names, a1, r, are commonly used in relationship to geometric sequences. We assume you want the terms of a geometric sequence with these characteristics.
a1 is the first term. r is the ratio between terms, so is the factor to find the next term from the previous one.
a1 = 3 (given)
a2 = a1×r = 3×(-2) = -6
a3 = a2×r = (-6)(-2) = 12
a4 = a3×r = (12)(-2) = -24
a5 = a4×r = (-24)(-2) = 48
The first 5 terms are 3, -6, 12, -24, 48.
__
The explicit formula for the terms of a geometric sequence is ...
an = a1×r^(n -1)
Using the given values of a1 and r, the explicit formula for this sequence is ...
an = 3(-2)^(n -1)
The denominator of a fraction is 1 more than 3 times the numerator. If the denominator is doubled and the numerator is increased by 2, the value of the resulting fraction is 1/4. Find the original fraction.
No BC it's ssa............
Answer:




Step-by-step explanation:
Given
I will answer this question using the attached triangle
Solving (a): Sine and Cosine A
In trigonometry:
and

So:

Substitute values for BC and BA




Substitute values for AC and BA



Solving (b): Sine and Cosine B
In trigonometry:
and

So:

Substitute values for AC and BA




Substitute values for BC and BA



Using a calculator:

So:

-- approximated

-- approximated

So:

--- approximated

--- approximated