Statistics - Speech or Presentation Example

Statistics On comparing the statistics results given regarding the three statistical results; Mean = 34.69 corresponding to a SD of 7.944, Mean = 33.89 corresponding to a SD of 10.380 and a Mean of 38.84 with a SD of 12.791 it can be construed that there is a substantial difference between the values statistically. The most important factor to consider when making this decision is the sample size of the students considered to obtain the various statistical values above. For instance, the mean that is considered in the statistical values is an average of samples and assumes that all the samples have the same values as indicated.

Standard deviation on the other hand show us how the individual values compares the mean value, the smaller the standard deviation, the closer the samples measurements are to the mean and vice versa (Gravetter and Wallnau 123). With regard then to the standard deviation given, it is evidenced that there is a considerable difference of the samples considered. Different sample numbers and variation of age among the considered students may have occasioned this. Comparing the two calculated statistics with the population statistics clearly shows inaccuracy, the mean deviation of the samples from that of the population is enormous and this shows that sampling was skewed to a section of the population thus the true value could not be reached.

This can also be observed with the values of the standard deviation that shows consistent abnormal variation questioning the sampling technique. Referring to the statistics from the samples against that of the population, they do not reflect values that are consistent to the central tendency. Central tendency tends to show us where the majority of the data belongs to by use of mode, median or mean (Gravetter and Wallnau 156). Indeed the only way of getting correct statistical results from a data is to consider as much samples as possible against the possible number of population, this will ensure that a larger percentage of the population are considered with possible inclusion of all the extremities, smaller and larger ones narrowing the space for biasness (Gravetter and Wallnau 162).

The use of two classes alone or Susan’s class would have considered a group with skewed values distorting the results.Works CitedGravetter, Frederick J. and Larry B Wallnau. Essentials of Statistics for the Behavioral Sciences. Belmont: Cengage Learning, 2010. Print.