The Normal Distribution and Probability Research Paper

The Normal Distribution and Probability - Research Paper Example The variable of interest, as with any other ratio variable, has a true zero point. That is, it is possible for a participant to not type any word in one minute but may not be able to type any lower than that value. This true zero point is what separates interval level variables from ratio level variables (Agresti & Finlay, 2009, p. 107). Ratio level of measurement is considered the highest level of measurement because many descriptive statistics computations and inferential statistics techniques may be performed on such measures (Cohen, 1988, p. 53). Specifically, it is possible to find the mode (though not applicable on this particular example), median, mean, range, maximum, minimum, and standard deviation for ratio level measures. This variable is normally distributed because the values that it takes may be scattered on a plot, approximating a symmetric bell-shaped curve (Kazmier, 2004). That is, the graph is more concentrated on the central values and symmetrically decreases on both side of the bell-shaped graph. This is possible because more people can type the â€Å"average† range of values for words per minute and as these values go to the extremes (whether extreme high or extreme low), fewer people fall into those values. In terms of central tendencies, it is to be expected that the mean, median, and modal value for number of words typed per minute would be most likely the same value (Agresti & Finlay, 2009). Furthermore, since the sample size is quite large, normal distribution of data points almost always follows (Rubin, 2009). In a normal distribution, the probability value of a particular score is the likelihood of that score occurring in the sample data (which may be carried over to the population). In this particular example, it is the percentage of participants that typed a particular number of words per minute. Moreover, a