1. Design and data analisis in Psychology I
Chapter 4

2. Practice 1
Calculate the P75 and the semiinterquartile deviation from a symmetric distribution with the D5 =30 and Q1=22.

3. Practice 2
Indicate the amount of X values from the following data set which distribution is symmetric and the mean is 7:
X, X, X, X, X, X, 6, 2, 3, 1, 3, 2

4. Practice 3
What is the Q value from a data set which partial information are specifying in the following table?:

5. Practice 4
The following table contain the data obtained by a sample in one psychological test:
Calculate the homogeneity index more appropriate.

6. Practice 5
In one distribution variable we know that the P25 = 40, the mean match with one of the quartiles and the semiinterquartile deviation is 10. Calculate the mean knowing that it’s higher than the median.

7. Practice 6
The following data table, contain the results obtained by one sample in a concrete psychological test.
With these data calculate the semiinterquartile deviation and the total amplitude.

8. Practice 7
With the data obtained by a sample in one test, reflecting in the following table, calculate the Pearson’s CV:

9. Practice 8
With the following data, calculate the semiinterquartile deviation:

10. Practice 9
With the following data set, which contain information about the number of answers said correctly by a scholar group in a test, calculate the central tendency indexes and the standard deviation:

11. Practice 10
In a hospital 2 groups of 20 children with learning problems was receiving treatment with 2 psychologists (A and B). When the treatment ended, we administrated one test which punctuation depends on the amount of problems correctly did it. The results obtained by the 2 groups are the following:
A) Which group obtained better results in the test?
B) Which group present higher level of variability?