9a - ab + 5bif a = 2 and b = 7
1 answer:
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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.