RES 341 FINAL EXAAM 5

# RES 341 FINAL EXAAM 5

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1) What is the difference between probability sampling and simple random sampling?
A. Probability sampling is a type of simple random sample.
B. In probability sampling each item has an identical chance of being chosen.
C. There is no difference.
D. Simple random sampling is a type of probability sampling.

2) A survey was mailed to a total of 400 students; 100 were randomly selected from each of the freshman, sophomore, junior and senior classes last semester. What sampling method was used?
A. Stratified sample
B. Simple random sample
C. Cluster sample
D. Systematic sample

3) A sufficiently large coverage error will result in which of the following?
A. Probability sampling
B. Inability to perform inferential statistics
C. Non-response bias
D. Statistics about the actual population rather than the target population

4) Which of the following statements is false?
A. Statistical inference is the process of making a prediction based on only a small piece of information.
B. A summary measure calculated from all items of interest is a parameter.
C. The main goal of descriptive statistics is to estimate characteristics of populations.
D. A summary measure calculated from some of the items of interest is a statistic.

5) Which of the following statements is NOT true?
A. A statistical test may be significant yet have no practical importance.
B. Scientific progress consists of continual refinement of theories through hypothesis testing.
C. Estimating parameters is an important aspect of descriptive statistics.
D. Statistics is the science of collecting, organizing, analyzing, interpreting, and presenting data.

6) Which of the following is an example of statistical inference?
A. Calculating the amount of fly spray needed for your orchard next season.
B. Counting the number of patients who file malpractice suits after being discharged from hospitals in New York State.
C. Calculating the mean age of patients discharged from hospitals in New York State in 1997.
D. Calculating the mean number of fruit trees damaged by Mediterranean fruit flies in California last year.

7) If terms such as positive, negative, more than, and less than, are used, then these hypotheses are_________.
A. nondirectional hypotheses
B. directional hypotheses
C. null hypotheses
D. alternative hypotheses

8) The manipulation of the independent variable is known as the ________.
A. experimental test
B. treatment
C. randomization
D. validity

9) Which of the following is NOT a potential source of survey error?
A. Systemic error
B. Sampling error
C. Nonresponse bias
D. Selection bias

10) Which of the following is NOT a potential source of survey error?
A. Interviewer error
B. Standard error
C. Measurement error
D. Coverage error

11) Which of these is NOT an acceptable type of survey question?
A. pictograms
B. Likert scale
C. ranking questions

12) Which of the following is NOT an ethical concern for the statistical researcher?
A. Informed consent
B. Protection of confidentiality
C. Use of sound methodology
D. Monetary compensation

13) Which of the following is not an ethical concern for the statistical researcher?
A. Manipulation of data
B. Privacy of privacy
C. Inhumane treatment of animals
D. Cite sources

14) Which of the following is NOT an ethical concern for the statistical researcher?
A. Accurate reporting of procedures
B. Accepted procedures are followed
C. Maintain data accuracy
D. Conceal financial support
15) A study of the scores on an in plant course in management principles and the years of service of the employees enrolled in the course yielded the following statistics: Test Scores: mean=100 variance = 225 Years of Service: mean=5 variance = 81 Of test scores and years of service, which measure has the greater dispersion?
A. The short-run effects of those changes are always more beneficial to society than are the long-run effects.
B. Test scores
C. Years of service
D. It is impossible to tell.

16) Textbook Price Number of Textbooks \$25 to \$35 2 35 to 45 16 45 to 55 5 55 to 65 7 65 to 75 20 Estimate the standard deviation of the price of a textbook.
A. 196.78
B. 14.03
C. 33.85
D. 729.00

17) Textbook Price Number of Textbooks \$25 to \$35 2 35 to 45 16 45 to 55 5 55 to 65 7 65 to 75 20 Estimate the mean price of a textbook.
A. \$60.00
B. \$554.00
C. \$11.08
D. \$55.40

18) Which measurement uses absolute values?
A. ratio correct
B. ordinal scale
C. interval scale
D. harmonic scale

19) Identify the scale which has no meaningful zero.
A. nominal
B. ordinal
C. ratio
D. interval

20) Which of these measurement scales has a rank order associated with its use?
A. Ratio
B. Ordinal
C. Likert
D. Nominal

21) Which of the following cannot generate a Poisson distribution?
A. The number of people at a movie theatre on Friday evening
B. The number of customers arriving at an ATM in a minute
C. The number of goals in the World Cup soccer game
D. The number of defects in a new automobile
22) The local police department must write, on average, 5 tickets a day to keep department revenues at budgeted levels. Suppose the number of tickets written per day follows a Poisson distribution with a mean of 5.5 tickets per day. Interpret the value of the mean.
A. The number of tickets written most often is 5.5 tickets per day
B. Half of the days have less than 5.5 tickets written and half of the days have more than 5.5 tickets written
C. The mean cannot be interpreted.
D. If we sampled all days, the arithmetic average or expected number of tickets written would be 5.5 tickets per day.
23) Ten bolts were selected randomly from a production line and the diameter of each was measured. Why do these diameters not have a binomial distribution?
A. They have equal probability of success.
B. The diameters of the bolts are not independent of one another.
C. They do have a binomial distribution.
D. Diameter is a continuous random variable.

24) The Big Red Arcade and Pizza Palace caters to young teens and sells tokens to play arcade games for 25¢ each and slices of pizza for 50¢ each. The distribution of sales of pizza slices per customer and sales of arcade tokens per customer is below. # Slices of Pizza 0 1 2 3 4 5 Probability 0.05 0.10 0.20 0.30 0.15 0.20 # Arcade Games 0 1 2 3 4 5 Probability 0.01 0.04 0.15 0.20 0.25 0.35 What is the probability that revenues from pizza slice sales will be greater than \$1.00 per customer?
A. .95
B. .65
C. .43
D. .85

25) Which of these parameters associated with a binomial experiment will produce a probability distribution with the smallest standard deviation; given n is the same for each situation?
A. p = 0.3
B. p = 0.5
C. (1- p) = 0.1.
D. p = 0.4

26) The average qualifying speed for a championship NASCAR race is 145.65 mph and the standard deviation is 9.45 mph. Only drivers who obtain z-scores greater than 1.2 will qualify for the race. If the speeds are normally distributed, what minimum speed must be clocked to compete for the trophy?
A. 157.0 mph
B. 146.9 mph
C. 174.8 mph
D. 155.2 mph

27) The use of the student’s t distribution requires which of the following assumptions?
A. The population is normal
B. The sample size is greater than 30
C. The sample is drawn from a positively skewed distribution
D. The population variance is known
28) The expected value of the sampling distribution of the sample mean equals the population mean
A. when the population size N > 30.
B. when the population is normally distributed.
C. for all populations.
D. when the population is symmetric.

29) Which of the following statements is consistent with the Central Limit Theorem?
A. When we know s, the variation in the sample means will be equal to that of the population.
B. When µ and s are known, the population will be approximately normally distributed.
C. Means of samples of n=30 from an exponential distribution will be approximately normally distributed.
D. If a population has µ and s, a sample from that population will be normally distributed if the sample size is large enough.

30) A study of 200 insomniacs paid for by the Serta Mattress Company found that the average insomniac counted 350 sheep before falling asleep, with a standard deviation of 120. An insomniac is a person who has difficulty falling asleep. Some useful numbers might be: =NORMSINV(0.89) 1.2265 =NORMSINV(0.945) 1.5982 =TINV(0.89,199) 0.1385 =TINV(0.11,199) 1.6053 =TINV(0.055,199) 1.9302 Out of the 200 insomniacs, 98 reported regularly watching The Late Show with David Letterman before they began to count sheep.Calculate the margin of error for a 78% confidence interval of the true proportion of insomniacs who regularly watch David Letterman before counting sheep.
A. 0.136
B. 0.043
C. 0.164
D. 0.056
31) A random sample of 25 observations is selected from a normally distributed population. The sample variance is 10. In the 95% confidence interval for the population variance, the upper limit will be
A. 17.331
B. 17.110
C. 19.353
D. 6.097
32) Summary statistics computed from two independent samples are as follows: n1 = 50, x1 = 175, s1 = 18.5, n2 = 42, x2 = 158, and s2 = 32.4. Construct a 95% confidence interval estimate for the difference between the means of two normally distributed populations, where the unknown population variances are assumed to not be equal. The upper confidence limit is
A. 19.123.
B. 28.212.
C. 24.911.
D. 5.788.

33) When the only sources of variation in a production process are caused by chance, the process is said to be
A. out of balance but under control.
B. out of control but in balance.
C. under control.
D. out of control.

34) When the results of a process are either defective or acceptable, the charts used for SPC are called
A. control charts for attributes.
B. control charts for variables.
C. control charts for in control process.
D. control charts for out of control process.

35) When no point lies outside the control limits of a chart, we conclude that variation in the process is
A. due to special causes and there is not enough evidence to infer that the process is out of control.
B. due to special causes and there is enough evidence to infer that the process is under control.
C. due to common cause and there is enough evidence to infer that the process is out of control.
D. due to common cause and there is not eno