60 is 30% of what number?
1 answer:
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Answer:
The standard deviation of number of hours worked per week for these workers is 3.91.
Step-by-step explanation:
Problems of normally distributed samples can be solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by
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. Subtracting 1 by the pvalue, we This p-value is the probability that the value of the measure is greater than X.
In this problem we have that:
The average number of hours worked per week is 43.4, so .
Suppose 12% of these workers work more than 48 hours. Based on this percentage, what is the standard deviation of number of hours worked per week for these workers.
This means that the Z score of has a pvalue of 0.88. This is Z between 1.17 and 1.18. So we use
.
The standard deviation of number of hours worked per week for these workers is 3.91.