Business Statistics Exam Study Guide100 Practice Questions & Worked
Problems with Solutions and Explanations 2026/2027
Practice case 1
Describing weekly sales
Five weekly unit-sales observations are 10, 12, 12, 16, and 20. Treat these as the
complete data set for these descriptive questions.
1. How many observations are present?
Working or response
2. Find the arithmetic mean.
Working or response
3. Find the median.
Working or response
4. Find the mode.
Working or response
5. Find the range.
Working or response
,Practice case 2
Sample dispersion
A random sample of four service times is 2, 4, 6, and 8 minutes. Use sample variance,
not population variance.
6. Find the sample mean.
Working or response
7. Find the sum of squared deviations.
Working or response
8. Find the sample variance.
Working or response
9. Find the sample standard deviation.
Working or response
10. Find the sample coefficient of variation.
Working or response
,Practice case 3
Weighted observations
Ten invoices have values of $50 for 2 invoices, $60 for 3 invoices, and $80 for 5
invoices.
11. Find the total invoice value.
Working or response
12. Find the mean invoice value.
Working or response
13. What proportion of invoices are $80?
Working or response
14. What percentage of total dollar value comes from $80 invoices?
Working or response
15. Find the median invoice value.
Working or response
, Practice case 4
Events and overlap
In a customer population, P(A) = 0.40, P(B) = 0.30, and P(A and B) = 0.10.
16. Find P(A or B).
Working or response
17. Find P(neither A nor B).
Working or response
18. Find P(A given B).
Working or response
19. Are A and B independent?
Working or response
20. Are A and B mutually exclusive?
Working or response
Problems with Solutions and Explanations 2026/2027
Practice case 1
Describing weekly sales
Five weekly unit-sales observations are 10, 12, 12, 16, and 20. Treat these as the
complete data set for these descriptive questions.
1. How many observations are present?
Working or response
2. Find the arithmetic mean.
Working or response
3. Find the median.
Working or response
4. Find the mode.
Working or response
5. Find the range.
Working or response
,Practice case 2
Sample dispersion
A random sample of four service times is 2, 4, 6, and 8 minutes. Use sample variance,
not population variance.
6. Find the sample mean.
Working or response
7. Find the sum of squared deviations.
Working or response
8. Find the sample variance.
Working or response
9. Find the sample standard deviation.
Working or response
10. Find the sample coefficient of variation.
Working or response
,Practice case 3
Weighted observations
Ten invoices have values of $50 for 2 invoices, $60 for 3 invoices, and $80 for 5
invoices.
11. Find the total invoice value.
Working or response
12. Find the mean invoice value.
Working or response
13. What proportion of invoices are $80?
Working or response
14. What percentage of total dollar value comes from $80 invoices?
Working or response
15. Find the median invoice value.
Working or response
, Practice case 4
Events and overlap
In a customer population, P(A) = 0.40, P(B) = 0.30, and P(A and B) = 0.10.
16. Find P(A or B).
Working or response
17. Find P(neither A nor B).
Working or response
18. Find P(A given B).
Working or response
19. Are A and B independent?
Working or response
20. Are A and B mutually exclusive?
Working or response
