Answer:
a. 1.44
Step-by-step explanation:
We are interested in determining whether or not the proportion of the population in favor of Candidate A is significantly more than 40%.
At the null hypothesis, it is tested if the proportion is of at most 40%, that is:
At the alternative hypothesis, it is tested if the proportion is of more than 40%, that is:
The test statistic is:
In which X is the sample mean, 
is the value tested at the null hypothesis, 
is the standard deviation and n is the size of the sample.
0.4 is tested at the null hypothesis:
This means that 
A random sample of 200 people was taken. 90 of the people in the sample favored Candidate A.
This means that:
Value of the test statistic:
Thus the correct answer is given by option a.
The topics you should learn are equating denominators and fractions. This is summing up simple fractions.
So we have to make denominators' numbers the same in order to sum up them all (we can sum fractions if the denominators are the same) , and we did it by cross product (that thing on the picture)
Equating by lcm (least common multiple) is the easiest way, because you might see bigger numbers on other questions, and cross product will bring much bigger numbers, so this technic might confuse you.
By the way lcm of 4 and 5 is already 20
Hope it helps!
Answer:
.0000111
Step-by-step explanation:
move the decimal five places to the left because the 5 is negative
