We need to think, 28 / 42 = x / 54.
We need to do a proportion for this problem!
First, line up both fractions, then put a equal sign between both fractions.
28 / 42 = x / 54.
We multiply in a diagonal and then we divide by the one without a diagonal.
28 and 54 are a diagonal.
We multiply both numbers!
54 x 28 = 1,512.
Then, we divide by 42.
1,512 / 42 = 36.
Therefore, x = 36.
+1 Picture :)
Answer: 13
Step-by-step explanation:
If the prior population proportion is unavailable then the formula to find the sample size is given by :-
, where z* = Critical z-value
E = margin of error
Let p be the proportion of Americans who support the gun control in 2018.
As per given , we have
Confidence level = 99%
The critical z-value for 99% confidence interval is 2.576 ( BY z-table)
Margin of error : E= 0.36
Since there no prior information about the proportion of Americans who support the gun control in 2018.
So , the required sample size to estimate 99% confidence interval would be:
Hence, 13 Americans should be surveyed.
Answer:
A
Step-by-step explanation:
We take a look at this expression: and notice that both terms are square numbers.
and
.
There is a specific formula that I highly recommend you memorize involving differences of squares. It states that given the difference of squares , it can always be factored into
.
Here, we can apply that. In this case, a = 7x and b = 3. So:
Thus, the answer is A.
Hope this helps!