Basic Statistics- Part III

Correlations

Definition:

  • Measures the strength of the relationship between two variables
  • Correlation coefficient (r) are values that can range from –1 to +1, and reflects the absolute value of the strength of the relationship
  • If the absolute value is close to 1, the relationship is considered to be strong; if it is close to 0, it is considered weak

Steps in SPSS

  1. 1.Click on the statistics option on the top row. Then move your cursor to Correlate, and then click on Bivariate.
  2. 2.This brings you to the Bivariate Correlations window. Move the relevant variables over to the variable pane.
  3. 3.Click on Options on the bottom right hand corner of the window. This will bring you to the Bivariate Correlations: Options Window.
  4. 4.Click on means and standard deviations to provide these statistics, and then click on Continue. This brings you back to the Bivariate Correlations Window.
  5. 5.Click on OK to run Correlations.

Output

  • There will be two tables of output.
  • In the first table, you will find the descriptive statistics for the variables (i.e., mean, standard deviation, and sample size)
  • The second table will be the correlational matrix.
  • This table is symmetric, in that the values above the diagonal are the same as the values below the diagonal
  • The first section of the table presents the correlation coefficients (r). The asterisk (*) following this correlation indicates that the correlation is significant at the .05 level (** indicates a significant correlation at the .01 level).
  • The second section of the table presents the actual probabilities associated with each correlation
  • The third section of the table shows the sample size on which each correlation is based.

Example

  • The following output is for a study that examined the relationship between cognitive specific imagery and the amount of physical and technical preparation used in the off-season.

PHYSICAL / TECHNICAL
CS
Pearson Correlation
Sig. (2-tailed)
N / .426**
.00
329 / .463**
.00
327
  • In the paper, these results would be report as followed.

“ Bivariate correlations were calculated to examine whether imagery use was related to the amount of physical and technical preparation that athletes engage in during the off-season. These correlations are presented in Table 1, and indicate that a positive, significant relationship existed between cognitive specific imagery and physical preparation (r = .43, p = .00) and between cognitive specific imagery and technical preparation (r = .46, p = .00).”