4.)What does it mean for a sample to have a standard deviation of zero? Describe the scores in such a sample.

6.) A population has a mean of =80 and a standard deviation of = 20.

a. would a score of X = 70 be considered an extreme value (out in the tail ) in this sample?

b. If the standard deviation were =5 , would a score of X= 70 be considered an extreme value?

For Items 16 and 18, please show the steps taken (show your work):

16.) Calulate SS, variance, and standard deviation for following sample of N= 4 scores: 7,4,2,1 ( note: the computational formula works well with these scores)

18.) Calulate SS, variance, and standard deviation for the following population N=7 scores : 8,1,4,3,5,3,4 ( Note: the definitional formula works well with these scores)

20.) For the following population of N= 6 Scores: 3,1,4,3,3,4

a. sketch a histogram showing the population distribution ( using SPSS)

b.Locate the value of the population mean in your sketch and make an estimate of the standard deviation.

c. compute SS, variance, and standard deviation for the population. (How well does your estimate compare with the actual value of ?)

22.) In an extensive study involving thousands of british children, Arden and Plomin ( 2006) found significantly higher variance in the intelligence scores for males than for females. Following are hypothetical data, similar to the results obtained in the study. Note that the scores are not regular IQ scores but have been standardized so that the entire sample has a mean of M=10 and a standard deviation of s=2.

a.calculate the mean and the standard deviation for the sample of n=* females and for the sample n=8 males

b.based on the means and the standard deviations,describe the differences in intelligence scores for males and femals

____________________

female male

____________________

9 8

11 10

1011

13 12

86

9 10

11 14

9 9

______________________

Additional Items:

1. Every population has a parametric mean () and parametric standard deviation (). Briefly discuss the impact of sample size on these parametric values.

2. Fact: by increasing sample size, the researcher does not reduce the size of the parametric standard deviation () but does decrease the uncertainty associated with the estimation of parametric values. Briefly explain the implications of this fact.

3. The concept of Degrees of Freedom re-appears throughout the study of statistics. Given a sample size of five (), what are the degrees of freedom? Provide a detailed example using real numbers.