answer is C 1/4
see attached picture, it is not exact but with rounding it comes out correct.
The one on the bottom says: tonight, Duane needs to bring home only his math and science textbooks. Tomorrow, he has to bring hi
s science project to school. His project weighs 5 pounds. Find the total weight Duane will carry in his backpack tomorrow.
2 answers:
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Answer:
P(X ≤ 94) = 0.09012
From what we observe; There is a probability of less than 94 people who voted for the referendum is 0.09012
Comment:
The result is unusual because the probability that p is equal to or more extreme than the sample proportion is greater than 5%. Thus, it is not unusual for a wrong call to be made in an election if the exit polling alone is considered.
Step-by-step explanation:
From the information given :
An exit poll of 200 voters finds that 94 voted for the referendum.
How likely are the results of your sample if the population proportion of voters in the town in favor of the referendum is 0.52? Based on your result, comment on the dangers of using exit polling to call elections.
This implies that ;
the Sample size n = 200
the probability p = 0.52
Let X be the random variable
So; the Binomial expression can be represented as:
X Binomial ( n = 200, p = 0.52)
Mean = np
Mean = 200 × 0.52
Mean = 104
The standard deviation =
The standard deviation =
The standard deviation =
The standard deviation =
The standard deviation = 7.065
However;
P(X ≤ 94) because the discrete distribution by the continuous normal distribution values lies in the region of 93.5 and 94.5 .
The less than or equal to sign therefore relates to the continuous normal distribution of X < 94.5
Now;
x = 94.5
Therefore;
z = −1.345
P(X< 94.5) = P(Z < - 1.345)
From the z- table
P(X ≤ 94) = 0.09012
From what we observe; There is a probability of less than 94 people who voted for the referendum is 0.09012
Comment:
The result is unusual because the probability that p is equal to or more extreme than the sample proportion is greater than 5%. Thus, it is not unusual for a wrong call to be made in an election if the exit polling alone is considered.
The integral above is definite so we must first calculate for indefinite one.
Rule:
Now we apply this rule and get:
Or just simply:
Now we integrate: