You randomly choose an undergraduate student from a large state university. Let E be the event that the student is male, let F b
1 answer:
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Answer:
11.51% probability that the mean annual salary of the sample is between $71000 and $73500
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal probability distribution
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
Central Limit Theorem
The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean and standard deviation
, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean
and standard deviation
.
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
In this question, we have that:
What is the probability that the mean annual salary of the sample is between $71000 and $73500?
This is the pvalue of Z when X = 73500 subtracted by the pvalue of Z when X = 71000. So
X = 73500
By the Central Limit Theorem
has a pvalue of 0.1151
X = 71000
has a pvalue of 0.
0.1151 - 0 = 0.1151
11.51% probability that the mean annual salary of the sample is between $71000 and $73500
9514 1404 393
Answer:
- 160 ft (out from the river)
- 320 ft (parallel to the river)
Step-by-step explanation:
Let x represent the length of fence parallel to the river. Then the dimension of perpendicular to the river will be half the remaining fence: (640-x)/2. The total area will be ...
A = x(640-x)/2
This is the equation of a parabola that opens downward. It has zeros at x=0 and x=640, so its axis of symmetry is x = (0+640)/2 = 320. That is, the peak of the area curve is found when x=320.
The dimensions of the garden with the largest area are 160 ft wide by 320 ft long, where the long side is the river side.
