Use z-scores and the z-distribution table for this problem.
Formula:
z = (x - mean)/sd -->sd is standard deviation.
With your data:
z = (79 - 75)/8
I'll let you finish the calculation. Once you have the z-score, check the z-table for your probability. Remember that the problem is asking for "the proportion of a large class that scored BELOW you on a test" and find your value accordingly.
I hope this will help get you started.
Approximate the proportion for each of the following situations . in each case assume the values are appoximmately bell shaped.
The proportion of a large class that scored below you on a test of which the mean was 75, standard dev=8, and your score was 79.
1 answer
1 answer