Instructor’s name STP 231 Test 2A Spring 2012
STP 231 Statistics for Life Science MajorsInstructor’s Name Print Name______
Test #2 Spring 2012
Honor Statement:
By signing below you confirm that you have neither given nor received any unauthorized assistance on this exam. This includes any use of a graphing calculator beyond those uses specifically authorized by the Mathematics Department and your instructor. Furthermore, you agree not to discuss this exam with anyone until the exam testing period is over. In addition, your calculator’s memory and menus may be checked at any time and cleared by any testing center proctor or Mathematics Department instructor.
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Instructions:
a.)The exam is worth a total of 102 points; please make sure your exam has all pages before you begin. Problems 1-8 are worth 9 points and problems 9-13 are worth 6 points. Make sure that you have all 11 pages to your exam. If you do not have 11 pages, then contact the student worker at the check out desk.
b.)Show all work in detail or your answer will not receive any credit. Include appropriate units on all questions that apply. Write neatly and box all answers.
c.)Please ask the student worker at the check out desk if you need scratch paper.
d.)No calculators or computers that do symbolic algebra, like the Casio FX-2, TI-89, or TI- 92, may be used.
e.)The formulas and tables are shown on the last page. You may take these pages off to help you during the exam
f.)Part 1 of the exam is for free response. Show your work or explain the process for each problem to receive credit.
g.)Part 2 is the multiple choice part of the exam. A table is given on page three for you to write in the letter for the correct answer. You may take the first page off to help you write the correct letter in for each answer.
h.)You may have one 4 by 6 note card. It must not contain any worked out problems. It must be attached to the back of your test when the exam is turned in.
Circle your answer choice on the exam AND fill in the answer with the letter of the answer that you believe is the correct answer.
Problem Number / Letter of Answer / Problem Number / Letter of Answer / Problem Number / Letter of Answer1. / 5. / 10.
2. / 6. / 11.
3. / 7. / 12.
4. / 8. / 13.
XXXX / XXXXX / XXXXX / XXXXXXX / 14.
Use the following information for problems 1-3 to find the requested information
Birth weights for babies born within the “normal” gestational period of 37-43 weeks are normally distributed with a mean of 3432 grams, and a standard deviation of 482 grams.
1.What would be the percentage of babies would be born with birth weights between 3200 grams and 3600 grams?
A. 31.6 %B.63.7 %C.32.5 %D.67.5% E.None of these
2.What percentage of babies would be born weighing more than 4300 grams?
A. 3.6 %B. 3.9 %C. 3.3 %D. 2.9% E. None of these
3. If a group of 4 newborn babies are chosen at random, what percentage of the group mean baby weights would be less than 3700 grams?
A. 13.3 %B. 86.7 %C. 98.0 %D. 2.0 % E. None of these
4. An insurance company is interested in estimating the average age of women being hospitalized for cardiovascular issues. From a random sample of 16 women hospitalized for cardiovascular issues the mean age was 71.9 years, and the standard deviation for s was 13.85 years. Construct a 95% confidence interval for the population mean age of all women hospitalized for cardiovascular issues.
- 65.8 to 78.0 years B. 64.5 to 79.3 yearsC. 63.2 to 80.6 years
D. 61.8 to 82 yearsE. None of the above
5.According to one pizza producing company the amount of cheese in pounds on a medium sized pizza is a normally distributed variable. On a medium sized pizza the mean amount of pizza is 0.5 lbs and the standard deviation is 0.025 pounds. If 84.1% of the pizzas have more than 0.475 pounds of cheese on them, then what is the probability that three randomly chosen pizzas all have more than 0.475 pounds of cheese on them?
A. 0.841B. 0.159C. 0.012D. 0.595E. None of these
6. Dexamethasone. Dexamethasone is used to treat chronic lung diseases. In a double blind study this drug was used to treat premature infants for lung diseases due to prematurity. There is a concern that this drug decreases intelligence. At school age, an IQ test was given to the treatment group and the control group. Summary statistics for the IQ test results for the treatment group and the control group are shown below:
Sample / Group / Sample size / Sample mean IQ / Sample standard deviations1 / Control / 74 / 84.4 / 12.6
2 / Treatment / 72 / 78.2 / 15
If the degrees of freedom is 138, and the standard error then find the 95% confidence interval for the difference between the population means
- 2.39 to 10.01 pointsB. 0.77 to 11.63 pointsC. 1.65 to 10.75 points
D. 1.61 to 10.79 pointsE. None of the above
7.A machine fills and dispenses a normally distributed weight of 5 mg with a standard deviation of 0.05 mg of Vitamin E capsules. The capsules are rejected for being under filled if they are at the 3rd percentile or less. What amount of Vitamin E in the capsule corresponds to the 3rd percentile, the level at which the capsules are discarded?
A. 4.94 mgB. 4.91 mgC. 4.97 mg D. 4.86 mgE. None of these
Find the necessary sample size.
- The Bureau of Alcohol, Tobacco, and Firearms is concerned about the amount of lead in California wines. In previous studies, the BATF determined that the standard deviation for the amount of lead in the bottles was 162.5 parts per billion. If the standard error should be no more than 10 parts per billion, how many random wine bottles should be analyzed for their lead concentrations?
A.133B.17C.5D.265E.None of these
Determine the correct answer
9.The mean number of calories consumed daily for adult men in one city is 2400 and the standard deviation of the incomes is 219. The distribution of caloric intake is skewed to the left. For samples of size 50, which of the following statements best describes the sampling distribution of the mean?
A. is uniformly distributed.
B. is approximately normally distributed.
C.The distribution of is skewed to the right.
D.Nothing can be said about the distribution of .
E.None of these
10.Which statements are true about Normal Probability Plots?
1.Normal probability plots are used to determine if the data is normally distributed.
2.Normal probability plots are used to determine if the data contains outliers.
3.The data points are ranked from smallest to largest and are then plotted versus their normalized scores.
4.Transformations on the variable such as can be performed to transform non-normal distributions to normal distributions
A. 1, 2, 3B. 1, 2, 4C. 2, 3, 4D. 1, 3, 4E. 1, 2, 3, 4
11. Which of the following statements are true about sampling distributions?
1.The sample size affects the shape of the sampling distribution.
2.The mean of all of the samples in the sampling distribution is not affected by the sample size.
3.As the sample size increases, the sample means are closer to the population mean.
4.The calculation for the Z-score is the same for a variable as it is for the sampling distribution for .
5.and are the only parameters that can be estimated by a sampling distribution
A). 1, 3, 4B) 1, 2, 3C) 1, 2, 5D) 1, 2, 4, 5E) 1, 2, 3, 5
12.Find the
A.-1.28B.-1.34C.1.34D.1.28E.None of the these
13. Determine which of the following statements about confidence intervals are true. From a sample size of n = 106 adults, the body temperature was measured. If the 95% confidence interval for the body temperature is .
- We are 95% confident that the average body temperature of the all of the individuals in the population is between 98.08˚F and 98.32˚F
- We are 95% confident that the average body temperature of the 106 individuals in the sample is between 98.08˚F and 98.32˚F
- 99 % confidence interval is wider than a 95 % confidence interval
A) 2, 3B) 3C) 1D) 2E) 1, 3F) None of these
Formula Sheet
Descriptive MeasuresBinomial Probability
Probability Rules
Sampling Distribution of the Sample Mean
Confidence Interval for One Population Mean
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or
SP12 T2 Form A © 2012 Arizona State University, Department of Mathematics and Statistics