STAT 3321 - Exam 1- White, Spring 2010 - Printed Name______
In the lab what computer do you usually use? _____
By signing below I state that I understand that academic dishonesty can result in punishment resulting in at least a zero on this test and could include expulsion from the university and that all the work on this exam is mine.
Directions
1. Do not open exam until told.
2. Bubble in your last name, skip a space, and then your first name on the scantron. (NO IDS PLEASE)
3. Set all pagers and cell phones to silent and place on floor or backpack
4. When finished place your printed material inside your exam and place on desk in front.
5. Check the board for corrections to the exam before leaving.
6. You cannot use your phone (or any other internet-enabled device) as a calculator.
I have read and I understand all the directions above.
______
Signature
1. The 2.5 percentile of a distribution has …
a. 95% of the values between it and the mean.
b. none of the other answers are correct
c. 97.5% of the values below it.
d. 97.5% of the values above it.
2. What is the median of the following population of numbers? 1, 5, 7, 1, 3?
a. none of the other answers are correct
b. 3
c. 7
d. 1
3. In order to check the strength of the linear relationship we can use…
a. a sample slope, b1
b. a population mean
c. a pie chart
d. a correlation coefficient, r
4. Using the same set of values (1, 2, 3, 4, 5, 6, 15, 21, 37), which is larger: the sample standard deviation or the poplation standard deviation? Note that no calculations are required to answer this.
a. population standard deviation
b. sample standard deviation
c. they are equal in value
d. can not be determined
5. The largest error you would expect in a sample mean is called
a. the margin of error
b. the standard error
c. the standard deviation
d. the big error (do not make one by choosing this)
6. You believe that the numeric grade on an exam depends on the amount of hours studied. What would a slope of
1.5 indicate?
a. When the hour studied is zero, the average grade is 1.5
b. The range of the data is large enough to include 1.5 standard deviations from the mean
c. For each one hour studied, there is average increase of 1.5 in the grade.
d. 150% of the variation in the grades can be explained by variation in the hours studied.
7. If A and B are mutually exclusive, Pr(A) = 0.10, and Pr(B)=0.90, then what is the probability of A or B?
a. can not be determined
b. 0
c. 0.09
d. 1.00
8. Given n=27 and p=.6, what is the probability of finding exactly 4 successes? Choose the appropriate substitution.
a.
b. none of the other answers are correct
c.
d.
9. Given the table on the right, find the Pr (B1|A3)
A1 / A2 / A3B1 / 0.03 / 0.41 / 0.06
B2 / 0.17 / 0.19 / 0.14
a. 0.30
b. 0.59
c. 0.64
d. none of the other answers are correct
10. If Pr(A) = 0.2, Pr (B) = 0.50, and Pr(A | B) = 0.1, then what is the probability of A and B?
a. 0.70
b. none of the other answers are correct.
c. 0.50
d. 0.05
11. Suppose a population follows the bell-shaped distribution with =$70 and =$10, what is the probability that you will find a value within $20 of the population mean?
a. 97.5%
b. 100%
c. 95%
d. 68%
12. Non-sampling errors can occur due to
a. small sample sizes
b. skewed histograms
c. gremlins (good movie, bad choice of answer)
d. typing errors
13. When do proportions have the same values as probabilities?
a. when calculating a mean
b. under random sampling
c. always
d. in pie charts
14. The symbol represents
a. the population standard deviation
b. the population coefficient of correlation
c. the sample standard deviation
d. the sample variance
15. Which of the following is a measure of variability?
a. oven
b. range
c. microwave
d. camp fire
16. Which type of data collection allows cause-effect statements?
a. experiments
b. surveys
c. random sampling
d. convenience sampling
17. Suppose you have a binomial with n=10,000 and p=0.50. Assuming the distribution of the counts is mound-shaped symmetric, what is the value of x on the 16th percentile?
a. 4950
b. 5050
c. none of the other answers are correct
d. 9950
18. The angle of a pie slice in a pie chart is proportionate to
a. the color of the pie
b. a random sample
c. percent of values in a category
d. the frequency of the numbers in the numeric intervals
19. You are concerned about your grade on an exam. The exam consisted of 100 questions. Furthermore, suppose that on any one question, there is a 50% chance that you will get it correct. What procedure would you use to determine the probability of failing?
a. probability from pie charts
b. a scatter-plot
c. the textbook’s binomial table
d. the empirical rule
20. A standard error in a sample mean consists of
a. a random sample
b. means and variance
c. nothing really important (Hint: BAD, BAD CHOICE)
d. variability and knowledge
21. The empirical rule is used to …
a. calculate the probabilities of bell shaped curves.
b. calculate the probabilities of any histogram
c. estimate the sample mean of a bell curve
d. draw a judgment sample.
22. Scatterplots are used to evaluate
a. relationships between two quantitative variables.
b. relationships between two qualitative variables.
c. pie charts
d. random sampling
23. Which of the following is used to examine the relationship between two qualitative variables?
a. correlation
b. mean
c. variance
d. pivot table
24. Given n=25 and p=.4, find Pr(x≥3).
a. 0.9976
b. 0.0024
c. 0.9996
d. none of the other answers are correct.
25. In a set of 100 statistics students, 40% took mathematics the previous year. 25% of those who took math the previous year got an A on the first exam. However only 10% of those who did not take math the previous year got an A on the first exam. Suppose you know that someone got an A on the first exam, what is the probability that they took math within the previous year?
a. 1.60
b. 0.625
c. 0.40
d. none of the other answers are correct.
STAT 3321 - Exam 1- Blue, Spring 2010 - Printed Name______
In the lab what computer do you usually use? _____
By signing below I state that I understand that academic dishonesty can result in punishment resulting in at least a zero on this test and could include expulsion from the university and that all the work on this exam is mine.
Directions
1. Do not open exam until told.
2. Bubble in your last name, skip a space, and then your first name on the scantron. (NO IDS PLEASE)
3. Set all pagers and cell phones to silent and place on floor or backpack
4. When finished place your printed material inside your exam and place on desk in front.
5. Check the board for corrections to the exam before leaving.
6. You cannot use your phone (or any other internet-enabled device) as a calculator.
I have read and I understand all the directions above.
______
Signature
1. The largest error you would expect in a sample mean is called
a. the standard deviation
b. the big error (do not make one by choosing this)
c. the margin of error
d. the standard error
2. Using the same set of values (1, 2, 3, 4, 5, 6, 15, 21, 37), which is larger: the sample standard deviation or the poplation standard deviation? Note that no calculations are required to answer this.
a. they are equal in value
b. can not be determined
c. population standard deviation
d. sample standard deviation
3. The 2.5 percentile of a distribution has …
a. 97.5% of the values below it.
b. 97.5% of the values above it.
c. 95% of the values between it and the mean.
d. none of the other answers are correct
4. A standard error in a sample mean consists of
a. nothing really important (Hint: BAD, BAD CHOICE)
b. variability and knowledge
c. a random sample
d. means and variance
5. The symbol represents
a. the sample standard deviation
b. the sample variance
c. the population standard deviation
d. the population coefficient of correlation
6. Scatterplots are used to evaluate
a. pie charts
b. random sampling
c. relationships between two quantitative variables.
d. relationships between two qualitative variables.
7. If Pr(A) = 0.2, Pr (B) = 0.50, and Pr(A | B) = 0.1, then what is the probability of A and B?
a. 0.50
b. 0.05
c. 0.70
d. none of the other answers are correct.
8. Given the table on the right, find the Pr (B1|A3)
A1 / A2 / A3B1 / 0.03 / 0.41 / 0.06
B2 / 0.17 / 0.19 / 0.14
a. 0.64
b. none of the other answers are correct
c. 0.30
d. 0.59
9. The empirical rule is used to …
a. estimate the sample mean of a bell curve
b. draw a judgment sample.
c. calculate the probabilities of bell shaped curves.
d. calculate the probabilities of any histogram
10. What is the median of the following population of numbers? 1, 5, 7, 1, 3?
a. 7
b. 1
c. none of the other answers are correct
d. 3
11. Which of the following is used to examine the relationship between two qualitative variables?
a. variance
b. pivot table
c. correlation
d. mean
12. In order to check the strength of the linear relationship we can use…
a. a pie chart
b. a correlation coefficient, r
c. a sample slope, b1
d. a population mean
13. You believe that the numeric grade on an exam depends on the amount of hours studied. What would a slope of
1.5 indicate?
a. For each one hour studied, there is average increase of 1.5 in the grade.
b. 150% of the variation in the grades can be explained by variation in the hours studied.
c. When the hour studied is zero, the average grade is 1.5
d. the range of the data is large enough to include 1.5 standard deviations from the mean
14. Which of the following is a measure of variability?
a. microwave
b. camp fire
c. oven
d. range
15. If A and B are mutually exclusive, Pr(A) = 0.10, and Pr(B)=0.90, then what is the probability of A or B?
a. 0.09
b. 1.00
c. can not be determined
d. 0
16. The angle of a pie slice in a pie chart is proportionate to
a. percent of values in a category
b. the frequency of the numbers in the numeric intervals
c. the color of the pie
d. a random sample
17. Suppose a population follows the bell-shaped distribution with =$70 and =$10, what is the probability that you will find a value within $20 of the population mean?
a. 95%
b. 68%
c. 97.5%
d. 100%
18. Suppose you have a binomial with n=10,000 and p=0.50. Assuming the distribution of the counts is mound-shaped symmetric, what is the value of x on the 16th percentile?
a. none of the other answers are correct
b. 9950
c. 4950
d. 5050
19. Given n=27 and p=.6, what is the probability of finding exactly 4 successes? Choose the appropriate substitution.
a.
b.
c.
d. none of the other answers are correct
20. Given n=25 and p=.4, find Pr(x≥3).
a. 0.9996
b. none of the other answers are correct.
c. 0.9976
d. 0.0024
21. When do proportions have the same values as probabilities?
a. always
b. in pie charts
c. when calculating a mean
d. under random sampling
22. You are concerned about your grade on an exam. The exam consisted of 100 questions. Furthermore, suppose that on any one question, there is a 50% chance that you will get it correct. What procedure would you use to determine the probability of failing?
a. the textbook’s binomial table
b. the empirical rule
c. probability from pie charts
d. a scatter-plot
23. Non-sampling errors can occur due to
a. gremlins (good movie, bad choice of answer)
b. typing errors
c. small sample sizes
d. skewed histograms
24. In a set of 100 statistics students, 40% took mathematics the previous year. 25% of those who took math the previous year got an A on the first exam. However only 10% of those who did not take math the previous year got an A on the first exam. Suppose you know that someone got an A on the first exam, what is the probability that they took math within the previous year?
a. 0.40
b. none of the other answers are correct.
c. 1.60
d. 0.625
25. Which type of data-collection allows cause-effect statements?
a. random sampling
b. convenience sampling
c. experiments
d. surveys