The area of a rectangle is 44m2. Work out the missing length x.
2 answers:
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Answer:
The bulbs should be replaced each 1060.5 days.
Step-by-step explanation:
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.
In this problem, we have that:
How often should the bulbs be replaced so that no more than 1% burn out between replacement periods?
This is the first percentile, that is, the value of X when Z has a pvalue of 0.01. So X when Z = -2.325.
The bulbs should be replaced each 1060.5 days.
<h2>Answer with explanation:</h2>
Let p be the population proportion of parents who had children in grades K-12 were satisfied with the quality of education the students receive.
Given : Several years ago, 39% of parents who had children in grades K-12 were satisfied with the quality of education the students receive.
Set hypothesis to test :
Sample size : n= 1055
Sample proportion :
Critical value for 95% confidence :
Confidence interval :
Since , Confidence interval does not contain 0.39.
It means we reject the null hypothesis.
We conclude that 95% confidence interval represents evidence that parents' attitudes toward the quality of education have changed.