An accounting professor obtained a random sample of 112 final exam grades for an introductory accounting class:
(a) Consider the following Descriptive Statistics of the data generated by Excel (PHStat), comment on the parameters measuring central tendency, dispersion of accounting exam grades of 112 students.
As measures of central tendency, the median and mean of this sample indicate an average grade of 76-77. ...view middle of the document...
71 = 12
Frequencies (Accounting Grades)
Bin Frequency Percentage Cumulative Range %
50 0 0.00% 0.00%
60 8 7.14% 7.14%
70 23 20.54% 27.68%
80 39 34.81% 62.49%
90 30 26.79% 89.28%
100 12 10.71% 100.00%
Construct and comment on a histogram of the data
The histogram shows the grades to be approximately normally distributed. Given that the bin size is quite large it is difficult to make out any detail regarding skewness and kurtosis. There do not appear to be any major outliers.
(c) The data are summarized in the following stem-and-leaf display. Explain the meaning of this graph.
The numbers on the left hand side represent the “bins” (stem) while the numbers on the right hand side of each stem show individual values within in each bin. The graph shows that the majority of scores fall in the 70’s bin. There are a total of 112 values, a mean of 76.14 and a median of 77.
What percentage of these students obtained from 60 to under 80 points?...