What is the value of x when 1/3x = 9 1/2
1 answer:
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Answer:
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Let X the random variable that represent the Shear strength of a population, and for this case we know the distribution for X is given by:
Where and
And let represent the sample mean, the distribution for the sample mean is given by:
On this case
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability on this way:
And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.
Answer:
The area under the curve that represents the percent of women whose heights are at least 64 inches is 0.5.
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, or the area under the curve representing values that are lower than x. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X, which is the same as the area under the curve representing values that are higher than x.
In this problem, we have that:
Find the area under the curve that represents the percent of women whose heights are at least 64 inches.
This is 1 subtracted by the pvalue of Z when X = 64.
has a pvalue of 0.5.
1 - 0.5 = 0.5
The area under the curve that represents the percent of women whose heights are at least 64 inches is 0.5.