Friday

July 25, 2014

July 25, 2014

Posted by **Jason** on Tuesday, December 5, 2006 at 1:10am.

(a) Whatis the probability that a random chosen individual has a WAIS score of 105 or higher?

(b) What are the mean and standard deviation of the average WAIS score of x for a SRS of 60 people?

(C) What is the Probability that the average WAIS score of an SRS of 60 people is 105 or higher?

Use z-scores and the normal distribution table for these problems.

For example:

a) Use z-score formula: z = (x - mean)/sd

z = (105 - 100)/15 = 0.33

Look at a normal distribution table using z = 0.33 and determine the area under the curve that would represent this z-score and higher (upper tail of the distribution curve). That would then be your probability.

If a sample size is given, that needs to be computed into the formula:

z = (x - mean)/(sd/sqrt of sample size)

Note: sqrt = square root.

I hope this will get you started.

**Related Questions**

Statistics - The scores on the Webster test are approximately normal with u=100...

Statistics - Politicians are interested in knowing the opinions of their ...

statistics - 1) A scale measuring prejudice has been administered to a large ...

statistics - Scores on a test have a mean of 66 and Q3 of 81. The scores have a ...

statistics - It is known that the population mean for the Full Scale IQ of the ...

statistics - It is known that the population mean for the Full Scale IQ of the ...

statistics - It is known that the population mean for the Full Scale IQ of the ...

statistics - It is known that the population mean for the Full Scale IQ of the ...

STAT - The distribution of heights of a population of adults is approximately ...

Statistics - Find an example of application of Normal Distribution (or ...