Question

A personality test is administered to a large group of subjects. Five scores are shown below, in original units and in standard units. Fill in the blanks.

79 64 52 72 _
1.8 .8 _ _ -1.4

Answer 1

Use z-score formula to find the missing values.

z = (x - mean)/sd

sd = standard deviation

First you have to figure out the mean and standard deviation.

Let's look at the values you were given.
Between 64 and 79 is one standard deviation (1.8 - .8 = 1.0). Therefore, one standard deviation = 79 - 64 = 15.

Now we can find the mean using the formula. Let's use the first set of values.
1.8 = (79 - mean)/15
Solve the equation for the mean. You will find that the mean = 52.

Now you have mean = 52 and standard deviation = 15. You will be able to find the missing blanks by solving the z-score formula for the unknown variable you need in each case.

I hope this will help get you started.