To get the probability of Point P be placed within the circle L, we need to get the ratio between the area covered by the circle and the area covered by the rectangle.
The area of the circle is:
A train travels 150 miles in 3 hours. At this same rate, how many miles will it travel in 8 hours?
1 answer:
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Answer:
0.9544 = 95.44% probability that the sample mean time for reading comic books per week is between 5 and 7 hours.
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 problem, we have that:
What is the probability that the sample mean time for reading comic books per week is between 5 and 7 hours
This is the pvalue of Z when X = 7 subtracted by the pvalue of Z when X = 5. So
X = 7
By the Central Limit Theorem
has a pvalue of 0.9772
X = 5
has a pvalue of 0.0228
0.9772 - 0.0228 = 0.9544
0.9544 = 95.44% probability that the sample mean time for reading comic books per week is between 5 and 7 hours.