the mean of the commute time to work for a resident of a certain city is 28.8 minutes. assume the standard deviation of the comm
1 answer:
Answer:
The minimum percentage of the commuters in the city has a commute time within 2 standard deviations of the mean is 75%.
Step-by-step explanation:
We have no information about the shape of the distribution, so we use Chebyshev's Theorem to solve this question.
Chebyshev Theorem
At least 75% of the measures are within 2 standard deviations of the mean.
At least 89% of the measures are within 3 standard deviations of the mean.
An in general terms, the percentage of measures within k standard deviations of the mean is given by .
Applying the Theorem
The minimum percentage of the commuters in the city has a commute time within 2 standard deviations of the mean is 75%.
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Answer:
The data item is
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean and standard deviation
, the z-score 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 p-value, we get the probability that the value of the measure is greater than X.
Mean of 400 and a standard deviation of 60.
This means that
z=3
We have to find X when Z = 3. So
The data item is