Z-Score Practice Worksheet
Homework #1
1. Calculate the variance and standard deviation from the following data: 2, 3, 4, 7
2. If a sample has a variance of 89.5, what is its standard deviation? Can standard deviation be negative?
3. Calculate the variance and standard deviation from the following data: 4, 5, 3, 9
Z-Score Practice Worksheet
PLS 2330 Homework #2
Name _____________________________
*You will need to use Appendix B – Standard Normal Table for this homework.
1. Find the z-score for X = 20 based on the following data: 19, 17, 15, 12, 9
2. The following scores were obtained as part of a sample with mean 10 and standard deviation 2. For each score, find the appropriate z-score:
X = 11: z =
X = 12: z =
X = 25: z =
X = 3: z =
3. UNCP is becoming a more selective university (hypothetical) and will only admit students who place at least 2 z-scores above the mean on the SAT that has a mean of 980 and a standard deviation of 75. What is the minimum score that an applicant must obtain to be admitted to the university?
Z-Score Practice Worksheet
Homework # 3 Name _____________________________
1. A sample of n = 5 has values of 3, 5, 4, 7, 6. Calculate the t-statistic assuming the sample standard deviation is 2 and the sample came from a population with a mean of 9 for a one-tailed test that is right-tailed with a .05 level of significance. Would you accept or reject the null hypothesis?
2. Using the information you calculated in Question 1, suppose you are now conducting a one-tailed test that is left-tailed. Would you accept or reject the null hypothesis?
3. A sample of n = 7 has values of 4, 8, 2, 3, 9, 5, 6 Calculate the t-statistic assuming the sample standard deviation is 1.5 and the sample came from a population with a mean of 5 for a one-tailed test that is right-tailed with a .05 level of significance. Would you accept or reject the null hypothesis?
4. Using the information you calculated in Question 2, suppose you are now conducting a one-tailed test that is left-tailed. Would you accept or reject the null hypothesis?
Z-Score Practice Worksheet
Homework # 4 Name _____________________________
1. A sample of n = 6 has values of 3, 5, 4, 7, 6, 8. Calculate the t-statistic assuming the sample standard deviation is 1.15 and the sample came from a population with a mean of 5 for a one-tailed test that is right-tailed with a .05 level of significance. Would you accept or reject the null hypothesis?
2. Using the information you calculated in Question 1, suppose you are now conducting a one-tailed test that is left-tailed. Would you accept or reject the null hypothesis?
3. A sample of n = 10 has values of 4, 8, 2, 3, 2, 9, 5, 6, 12, 10 Calculate the t-statistic assuming the sample standard deviation is 2.25 and the sample came from a population with a mean of 7 for a one-tailed test that is right-tailed with a .05 level of significance. Would you accept or reject the null hypothesis?
4. Using the information you calculated in Question 2, suppose you are now conducting a one-tailed test that is left-tailed. Would you accept or reject the null hypothesis?