The scatterplot shows the average number of hours each of 12 people spends at work every week and the average number of hours ea
ch of them spends on recreational activities every week. Based on the scatterplot, what is the best prediction of the average number of hours a person spends on recreational activities every week if that person spends an average of 40 hours at work every week?
A) 17
B) 22
C. 28
D) 33
A) 17
B) 22
C. 28
D) 33
2 answers:
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Answer:
A score of 314 is needed to be in the top 25% of students who take this exam.
Step-by-step explanation:
We are given that one of the tests provided by the NAEP assesses the reading skills of twelfth-grade students. In recent years, the national mean score was 289 and the standard deviation was 37.
Let X = <u><em>scores of the tests provided by the NAEP</em></u>
The z-score probability distribution for the normal distribution is given by;
Z = ~ N(0,1)
where, = national mean score = 289
= standard deviation = 37
Now, we have to find how high a score is needed to be in the top 25% of students who take this exam, that means;
P(X > x) = 0.25 {where x is the required score}
P( >
) = 0.25
P(Z > ) = 0.25
In the z table, the critial value of z that represents the top 25% of the area is given as 0.6745, that is;
x = 289 + 24.96 = 313.96 ≈ 314
Hence, a score of 314 is needed to be in the top 25% of students who take this exam.