The following dataset represents a recent set of test results from a chemistry class. 90, 90, 95, 100, 80, 80, 75, 80, 70, 60, 95, 100, 100, 100, 75, 80, 90, 90, 90, 70, 70, 80, 85, 90, 90, 85
Use a statistics calculator (Links to external site.) to find the mean and standard deviation (rounded to the nearest tenth) of the data set.
Mean:
Sample standard deviation:
Draw the following diagram to help you solve the problem and label the mean and three standard deviations from the mean in both directions.
Use the diagram above and the mean and standard deviation you calculated to answer the following questions using the rule of thumb.
a) How many students in the chemistry course (that is, how many students out of 26) obtained a score less than 1 standard deviation from the mean? How does this compare to what the rule of thumb says should happen?
b) How many students in the chemistry course (that is, how many of the 26 students) obtained a score less than 2 standard deviations from the mean? How does this compare to what the rule of thumb says should happen? Impossible to schematize these messages. Can’t copy and paste here.