A set of 50 data values has a mean of 18 and a variance of 4.
I. Find the standard score (z) for a data value = 20.
II. Find the probability of a data value < 20.
III. Find the probability of a data value > 20.
Show all work.
Solution
assuming X ~ N(18, 4) so you would calculate z = (20-18)/4 [(X - mu)/ variance]
look up the z value for .5000 on the table, and that is the probability that x is less then or equal to
20 to find the probability of greater than 20, just take the fact that the probabilities add to 1 and
1 - the above probability is the probability that x is greater than 20..
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A set of 50 data values has a mean of 18 and a variance of 4. I. F.pdf
1. A set of 50 data values has a mean of 18 and a variance of 4.
I. Find the standard score (z) for a data value = 20.
II. Find the probability of a data value < 20.
III. Find the probability of a data value > 20.
Show all work.
Solution
assuming X ~ N(18, 4) so you would calculate z = (20-18)/4 [(X - mu)/ variance]
look up the z value for .5000 on the table, and that is the probability that x is less then or equal to
20 to find the probability of greater than 20, just take the fact that the probabilities add to 1 and
1 - the above probability is the probability that x is greater than 20.
![A set of 50 data values has a mean of 18 and a variance of 4.
I. Find the standard score (z) for a data value = 20.
II. Find the probability of a data value < 20.
III. Find the probability of a data value > 20.
Show all work.
Solution
assuming X ~ N(18, 4) so you would calculate z = (20-18)/4 [(X - mu)/ variance]
look up the z value for .5000 on the table, and that is the probability that x is less then or equal to
20 to find the probability of greater than 20, just take the fact that the probabilities add to 1 and
1 - the above probability is the probability that x is greater than 20.](https://image.slidesharecdn.com/asetof50datavalueshasameanof18andavarianceof4-230323133014-8ca3c8f8/85/A-set-of-50-data-values-has-a-mean-of-18-and-a-variance-of-4-I-F-pdf-1-320.jpg)
