Richard needed to read 5 books for his summer reading assignment. It took him 4 5/8 hours to read the first 2 books. It took him
2 answers:
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Answer:
a)
b)
c)
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Part a
Let X the random variable that represent the number of people of a population, and for this case we know that:
Where and
The central limit theorem states that "if we have a population with mean μ and standard deviation σ and take sufficiently large random samples from the population with replacement, then the distribution of the sample means will be approximately normally distributed. This will hold true regardless of whether the source population is normal or skewed, provided the sample size is sufficiently large".
From the central limit theorem we know that the distribution for the sample mean is given by:
And we want to find this probability:
And using a calculator, excel or the normal standard table we have that:
Part b
And using a calculator, excel or the normal standard table we have that:
Part c
For this case we want this probability:
And using a calculator, excel or the normal standard table we have that:
Answer: C (21)
Step-by-step explanation:
I am translating into algebra.
Set Scott's age five years ago to: x
Set Paul's age five years ago to: 2x-4
Scott's age now is his age five years ago, plus five, which is: x+5
Paul's age now is his age five years ago, plus five, which is: 2x-4+5 or 2x+1
Since Paul is now six years older than Scott, set Scott's age (x+5) equal to Paul's age, plus six, which is: 2x+1=x+5+6
Solve the equation to get: x=10
Substitute x for 10 in Paul's current age: 2*10+1=21.
Therefore, C is the correct answer.
