Allie bought a 5 pound bag of trail mix. she gave 12 Oz of trail mix to Justin. then she put the rest of the trail mix to into s
2 answers:
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Answer:
A normal distribution or z-test is used to construct a confidence interval.
Step-by-step explanation:
We are given the following in the question:
Sample mean, = $3120
Sample size, n = 40
Population standard deviation, σ = $677
The distribution of earnings of college is a normal distribution.
Conditions:
- Since we are given the population standard deviation and the the sample size is also greater than 30.
Conclusion:
Thus, we use a normal distribution or z-test to construct a confidence interval.
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.
Answer:
Conjecture : 2xy / ( x + y ) ≤ √xy
Step-by-step explanation:
Harmonic mean of x and y = 2xy/( x + y )
<u>Formulate a conjecture about their relative sizes </u>
we will achieve this by computing harmonic and geometric means
Geometric mean = √xy
harmonic mean = 2xy/( x + y )
Conjecture : 2xy / ( x + y ) ≤ √xy
attached below is the proof
