A researcher has recorded the reaction times of 20 individuals on a memory assessment. The following table indicates the individual times:
2.2 4.7 7.3 4.1
9.5 15.2 4.3 9.5
2.7 3.1 9.2 2.9
8.2 7.6 3.5 2.5
9.3 4.8 8.5 8.1
In this essay, demonstrate your ability to organize data into meaningful sets, calculate basic descriptive statistics, interpret the results, and evaluate the effects of outliers and changes in the variables. You may use Excel, one of the many free online descriptive statistics calculators, or calculate the values by hand and/or with a calculator.
Next, separate the data into two groups of 10; one group will be the lower reaction times, and the second group will be the higher reaction times. Then, address the following points in your essay response:
• Calculate the sum, mean, mode, median, standard deviation, range, skew, and kurtosis for each group.
• How do the two groups differ?
• Are there any outliers in either data group?
• What effect does an outlier have on a sample?
Lastly, double each sample by repeating the same 10 data points in each group. You will have a total of 20 data points for each group. After completing this, address the following in your essay response:
• Calculate the following for the new data groups: sum, mean, mode, median, standard deviation, range, skew, and kurtosis.
• Did any of the values change?
• How does sample size affect those values?
