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What is the minimum score needed to be in the bottom 10 percent of the normal distribution with a mean of 140 and a standard deviation of 55?
Wiki User
∙ 12y ago
To do this, you first need to convert the percentage into a z-score. The bottom 10% yields a z-score of -1.2816. Multiplying this by 55 and adding to the mean gives 69.512. This means all score less that are 69 or less will be in the bottom 10%
Wiki User
∙ 12y ago
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What percent of the scores in a normal distribution will fall within one standard deviation?
It is 68.3%
What are importance of mean and standard deviation in the use of normal distribution?
For data sets having a normal distribution, the following properties depend on the mean and the standard deviation. This is known as the Empirical rule. About 68% of all values fall within 1 standard deviation of the mean About 95% of all values fall within 2 standard deviation of the mean About 99.7% of all values fall within 3 standard deviation of the mean. So given any value and given the mean and standard deviation, one can say right away where that value is compared to 60, 95 and 99 percent of the other values. The mean of the any distribution is a measure of centrality, but in case of the normal distribution, it is equal to the mode and median of the distribtion. The standard deviation is a measure of data dispersion or variability. In the case of the normal distribution, the mean and the standard deviation are the two parameters of the distribution, therefore they completely define the distribution. See: http://en.wikipedia.org/wiki/Normal_distribution
Does 84 percent of people do higher than 1 standard deviation below the mean?
yes
What is the approximate standard deviation of returns if over the past four years an investment returned 8.0 percent 12.0 percent 12 percent and 15.0 percent?
s
How do you interpret if this is the data SD of 15.79 and mean of 126.9 or SD of 8.29 and mean of 124.7 also How do you know if the standard deviation is high and is there a highest possible SD?
n probability theory and statistics, thestandard deviation of a statistical population, a data set, or a probability distribution is the square root of itsvariance. Standard deviation is a widely used measure of the variability ordispersion, being algebraically more tractable though practically less robustthan the expected deviation or average absolute deviation.It shows how much variation there is from the "average" (mean). A low standard deviation indicates that the data points tend to be very close to the mean, whereas high standard deviation indicates that the data are spread out over a large range of values.For example, the average height for adult men in the United States is about 70 inches (178 cm), with a standard deviation of around 3 in (8 cm). This means that most men (about 68 percent, assuming a normal distribution) have a height within 3 in (8 cm) of the mean (67-73 in (170-185 cm)) - one standard deviation, whereas almost all men (about 95%) have a height within 6 in (15 cm) of the mean (64-76 in (163-193 cm)) - 2 standard deviations. If the standard deviation were zero, then all men would be exactly 70 in (178 cm) high. If the standard deviation were 20 in (51 cm), then men would have much more variable heights, with a typical range of about 50 to 90 in (127 to 229 cm). Three standard deviations account for 99.7% of the sample population being studied, assuming the distribution is normal (bell-shaped).
What percent of the scores in a normal distribution will fall within one standard deviation?
It is 68.3%
If a test has a normal distribution with a mean of 400 and a standard deviation of 100 what would be the minimum score for the top 3 percent of students?
(x-400)/100=1.882 x=588.2
Is the middle spread that is the middle 50 percent of the normal distribution is equal to one standard deviation?
false
What are importance of mean and standard deviation in the use of normal distribution?
For data sets having a normal distribution, the following properties depend on the mean and the standard deviation. This is known as the Empirical rule. About 68% of all values fall within 1 standard deviation of the mean About 95% of all values fall within 2 standard deviation of the mean About 99.7% of all values fall within 3 standard deviation of the mean. So given any value and given the mean and standard deviation, one can say right away where that value is compared to 60, 95 and 99 percent of the other values. The mean of the any distribution is a measure of centrality, but in case of the normal distribution, it is equal to the mode and median of the distribtion. The standard deviation is a measure of data dispersion or variability. In the case of the normal distribution, the mean and the standard deviation are the two parameters of the distribution, therefore they completely define the distribution. See: http://en.wikipedia.org/wiki/Normal_distribution
The mean plus or minus the standard deviation for a normal distribution provides a probability range of what percent?
in a normal distribution, the mean plus or minus one standard deviation covers 68.2% of the data. If you use two standard deviations, then you will cover approx. 95.5%, and three will earn you 99.7% coverage
How do you do percent variation?
Percent variation is the standard deviation divided by the average
What is the middle 95 percent of students who drink five beers with a standard deviation of 01 and a mean of 07?
Not possible to tell you without knowing how many students' there are, and what distribution you wish to use (i.e normal distribution, t-distribution etc...)
What percent of data falls between 1 Standard deviation below and 2 stand deviations above the mean?
The answer will depend on what the distribution is. Non-statisticians often assum that the variable that they are interested in follows the Standard Normal distribution. This assumption must be justified. If that is the case then the answer is 81.9%
On a normal distribution a score of 100 on the current IQ test with a standard deviation of 15 points would mean you scored higher than what percentage of the population?
50 percent
The weight of football players is normally distributed with a mean of 200 pounds and a standard deviation of 25 pounds. What is the minimum weight of the middle 95 percent of the players?
151 lbs
If average height for women is normally distributed with a mean of 65 inches and a standard deviation of 2.5 inches then approximately 95 percent of all women should be between what and what inches?
A normal distribution with a mean of 65 and a standard deviation of 2.5 would have 95% of the population being between 60 and 70, i.e. +/- two standard deviations.
If the mean is 1050 and the standard deviation is 218 what is the conpsumption level separating the bottom 45 percent from the top 55 percent?
The answer will depend on what the distribution is! And since you have not bothered to share that crucial bit of information, I cannot provide a more useful answer.
