All Algebra II Resources
Example Questions
Example Question #13 : Standard Deviation
If the mean is with a standard deviation of , then which of the following values is within one standard deviation?
If mean is with standard deviation of , then one standard deviation within has a range of to .
Remember, we find the range by adding the standard deviation to the mean and subtracting the standard deviation from the mean.
Only is in the range.
The rest of the numbers are more than one standard deviation.
Example Question #11 : Standard Deviation
If variance is , what is the standard deviation?
Variance is,
.
To find standard deviation is to take the sqaure root of the variance.
.
Example Question #412 : Basic Statistics
What is the difference between two standard deviations on the right tail with one standard deviation on the right tail? Assume a normal distribution.
Two standard deviations represents . One standard deviation represents . The difference is . However, the question is focusing on the right side of the tail. Since it's normal distribution, both tails of the graph are equal. Divide by and we get .
Example Question #16 : Standard Deviation
If the number set is within a standard deviation and the range is to , what is the standard deviation? Assume a normal distribution.
Since it's normally distributed, that means we can find the mean. The middle number in the number set is the mean. In this case that value is . Since it's within one standard deviation, we can take the difference of either and or and which the answer is either way.
Example Question #17 : Standard Deviation
If the number set is within standard deviations and the range is to , what is the standard deviation? Assume a normal distribution.
Since it's normally distributed, that means we can find the mean. The middle number in the number set is the mean. In this case that value is .
Since it's standard deviations, we need to set up an equation.
This is written like this because is the lowest number in the set, represents the standard deviations and is one standard deviation. By subtracting both sides and dividing both sides by , we get .
Example Question #12 : Standard Deviation
How many standard deviations represents of a set in a normal distribution?
Five
One
Three
Four
Two
Two
One standard deviation represents . Two standard deviations represents . Three standard deviations represents .
As you add more standard deviations, the percent coverages get a bit bigger.
The answer is just two.
Example Question #19 : Standard Deviation
Determine the population standard deviation of the following data set and round to three decimal places:
Write the formula for population standard deviation.
represents the number of terms, represents the terms in the data set, and is the mean.
Calculate the mean, .
Evaluate the variance, .
The standard deviation is the square root of the variance.
The answer is:
Example Question #484 : Algebra Ii
A jellybean machine dispenses 3 jellybeans on the first trial, 5 jellybeans on the second trial, and 7 jellybeans on the third trial. Determine the sample standard deviation.
The standard deviation measures the spread of the results.
Write the formula for the sample standard deviation.
Determine the mean .
The term means that we are summing the squared differences from the mean.
Simplify the terms.
represents the sample size. There are three numbers in the data.
The answer is:
Example Question #21 : Standard Deviation
Determine the sample standard deviation if the sample variance is .
Write the formula for the standard deviation given the variance.
Substitute the variance into the standard deviation.
The answer is:
Example Question #1 : Distributions And Curves
The ages of the students at GW High School are normally distributed with a mean of and a standard deviation of years.
What is the proportion of students that are younger than years old?
Not enough information to answer the question.
This question relates to the rule of normal distribution. We know that of the data are within standard deviations from the mean.
In this case this means that of the students are between
and
and
and
Therefore we have of the students that are outside of this range. Since the normal distribution is symmetric, the proportion of students below is the same as the proportion of students above .
Thus the right answer is or .
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