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If the scores for a test have a mean of 70 and a standard deviation of 12 what percentage of scores will fall below 50?
z=-20/12 = -1.667 Assuming normal distribution, P(Z < -1.667) = 0.04779 or 4.8% of the scores should be less than 50. You can get the probabilities by looking them up on a table or use Excel, where +Normdist(50,70,12,true). My normal table has only 2 digit accuracy so for -1.67 = 0.0475.
What else can I help you with?
When to you use a z-scores or t-scores?
T score is usually used when the sample size is below 30 and/or when the population standard deviation is unknown.
What percentage of scores falls between the mean and -2 to 2 standard deviations under the normal curve?
In a normal distribution, approximately 68% of scores fall within one standard deviation of the mean (between -1 and +1 standard deviations). About 95% of scores fall within two standard deviations (between -2 and +2 standard deviations). Therefore, the percentage of scores that falls specifically between the mean and -2 to 2 standard deviations is about 95% minus the 50% that is below the mean, resulting in approximately 45%.
What percentage is 1 standard deviation?
In a normal distribution, approximately 68% of the data falls within one standard deviation of the mean. This means that around 34% of the data lies between the mean and one standard deviation above it, while another 34% lies between the mean and one standard deviation below it.
What percentage of the area falls below the mean?
The area between the mean and 1 standard deviation above or below the mean is about 0.3413 or 34.13%
If a normally distributed group of test scores have a mean of 70 and a standard deviation of 12 find the percentage of scores that will fall below 50?
X = 50 => Z = (50 - 70)/12 = -20/12 = -1.33 So prob(X < 50) = Prob(Z < -1.33...) = 0.091
What Percent of population between 1 standard deviation below the mean and 2 standard deviations above mean?
In a normal distribution, approximately 68% of the population falls within one standard deviation of the mean, and about 95% falls within two standard deviations. Therefore, to find the percentage of the population between one standard deviation below the mean and two standard deviations above the mean, you would calculate 95% (within two standard deviations) minus 34% (the portion below one standard deviation), resulting in approximately 61% of the population.
How can you convert standard deviation into percentage?
There must be a formula, but in the mean time there is a handy site that does it for you. [See related link below for the converter]
What is the standard deviation of the data set given below?
A single number, such as 478912, always has a standard deviation of 0.
How do you find the standard deviation for data?
Standard deviation calculation is somewhat difficult.Please refer to the site below for more info
What is he standard deviation of the data set given below 478912?
A single number, such as 478912, always has a standard deviation of 0.
Scores on an exam are normally distributed with a mean of 76 and a standard deviation of 10 In a group of 230 tests how many students score below 66?
There are approximately 16.4% of students who score below 66 on the exam.
How many of the 100 scores are expected to be below 32.38 (two standard deviations above the mean)?
In a normal distribution, approximately 95% of the scores fall within two standard deviations of the mean. This means that about 5% of the scores will be below two standard deviations above the mean. Therefore, if you have 100 scores, you can expect around 5 scores to be below 32.38.
