IQ is distributed normally, with a mean of 100 and a standard deviation of 15. The z-score of 100 is therefore:
(value-mean)*standard deviation
= (100-100)*15
= 0
More generally, a raw score that is equivalent to the mean of a normal distribution will always have a z-score of 0.
112.8
A z-score of 0 means the value is the mean.
About 15.87% of people have an IQ over 115.z=(115-100)/15=1Z-score of 1 on a normal distribution means 84.13% have an IQ below 115 and 15.87% have an IQ above 115.IQ Graphhttp://8.17.172.75/uiq/images/bellcurve.gif
z-score of a value=(that value minus the mean)/(standard deviation). So a z-score of -1.5 means that a value is 1.5 standard deviations below the mean.
The z-score must be 1.87: the probability cannot have that value!
mean= 100 standard deviation= 15 value or x or n = 110 the formula to find the z-value = (value - mean)/standard deviation so, z = 110-100/15 = .6666666 = .6667
112.8
It is not possible to have an IQ of -1.0
Z = (x-mu)/sigma. So, for your example, any x value can be transformed to Z-score by the formula Z = (x-100)/20.
A z-score of 0 means the value is the mean.
z-score of a value=(that value minus the mean)/(standard deviation). So if a value has a negative z-score, then it is below the mean.
z-score of a value=(that value minus the mean)/(standard deviation)
z-score of a value=(that value minus the mean)/(standard deviation)
z-score of a value=(that value minus the mean)/(standard deviation)
A negative z score is a value that is less than the mean value.
About 15.87% of people have an IQ over 115.z=(115-100)/15=1Z-score of 1 on a normal distribution means 84.13% have an IQ below 115 and 15.87% have an IQ above 115.IQ Graphhttp://8.17.172.75/uiq/images/bellcurve.gif
z-score of a value=(that value minus the mean)/(standard deviation). So a z-score of -1.5 means that a value is 1.5 standard deviations below the mean.