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Study Resources (Statistics)

  31.A national manufacturer of ball bearings is experimenting with two different processes for producing precision ball bearings. It is important that the diameters be as close as possible to an industry standard. The output from each process is sampled and the average error from the industry standard is measured in.
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  92.A company is researching the effectiveness of a new website design to decrease the time to access a website. Five website users were randomly selected and their times (in seconds) to access the website with the old and new designs were recorded. The results follow.  What is the value of the.
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  103.The waiting time for patients at a local walk-in health clinic follows a normal distribution with a mean of 15 minutes and a population standard deviation of 5 minutes. The quality-assurance department sampled 50 patients and found that the mean waiting time was 14.25 minutes. What is the test statistic?    104.The.
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  65.The Intelligence Quotient (IQ) test scores for adults are normally distributed with a mean of 100 and a standard deviation of 15. What is the probability we could select a sample of 50 adults and find that the mean of this sample is between 98 and 103?    A. 0.3264 B. 0.9428 C. 0.4702 D. 0.7471 66.The tread life of.
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  113.A silkscreen printing company purchases t-shirts. To ensure the quality of the shipment, 300 t-shirts are randomly selected. Fifteen are defective. What is the estimated proportion defective in the population?    114.A silkscreen printing company purchases t-shirts. To ensure the quality of the shipment, 300 t-shirts are randomly selected. Fifteen are defective..
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  98.Increasing sample sizes result in _______________ interval estimates of a population parameter.    99.To compute a confidence interval for a population proportion, a __________ statistic is used.    100.For a given confidence level, the value of t ___________ as the sample size increases.    101.A finite population correction factor is used to adjust the _________________.    102.A finite.
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  51.A company is researching the effectiveness of a new website design to decrease the time to access a website. Five website users were randomly selected, and their times (in seconds) to access the website with the old and new designs were recorded. To compare the times, they computed (new website.
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  26.What is a Type II error?    A. Failing to reject a false null hypothesis B. Rejecting a false null hypothesis C. Accepting a false alternate hypothesis D. Rejecting a false alternate hypothesis 27.If the alternate hypothesis states that µ ≠ 4,000, where is the rejection region for the hypothesis test?    A. In both tails B. In the lower or left tail C. In the upper.
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  55.Bones Brothers & Associates prepare individual tax returns. Over prior years, Bones Brothers has maintained careful records regarding the time to prepare a return. The mean time to prepare a return is 90 minutes and the standard deviation of this distribution is 14 minutes. Suppose 100 returns from this year.
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  73.If the null hypothesis states that there is no difference between the two population means, then the test is ______________.    74.If a hypothesis states that one population mean is greater than another population mean, then the test is _______________.    75.When the population standard deviations are equal but unknown, a test for the.
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  46.Based on the Nielsen ratings, the local CBS affiliate claims its 11 p.m. newscast reaches 41% of the viewing audience in the area. In a survey of 100 viewers, 36% indicated that they watch the late evening news on this local CBS station. What is the p-value?    A. 0.3461 B. 0.1539 C. 0.3078 D. 0.0100 47.It is claimed that.
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  1.The F distribution's curve is positively skewed.    2.One characteristic of the F distribution is that the computed F can only range between -1 and +1.    3.If the computed value of F is 0.99 and the F critical value is 3.89, we would not reject the null hypothesis.    4.For the hypothesis test,   with n1.
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  1.An example of a hypothesis is: A person is innocent until proven guilty.    2.Hypothesis testing is a procedure that uses sample evidence and probability theory to decide whether to reject or fail to reject a hypothesis.    3.An alternate hypothesis is a statement about a population parameter that is accepted when the null.
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  11.To determine the size of a sample, the standard deviation of the population must be estimated by either taking a pilot survey or by approximating it based on knowledge of the population.    12.When using the t distribution to calculate a confidence interval, we assume that the population of interest is normal.
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  36.If the critical z value for a hypothesis test equals 2.45, what value of the test statistic would provide the least chance of making a Type I error?    A. 3.74 B. 10,000 C. 2.46 D. 4.56 37.For a one-tailed hypothesis test, the critical z value of the test statistic is -2.33. Which of the following is true about the.
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  81.If we are testing for the difference between two population means and assume that the two populations have equal but unknown standard deviations, then the test has ________ degrees of freedom.    82.A study by a bank compared the mean savings of customers who were depositors for three years or less with.
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  21.When testing the difference between two population means, the sample variances are pooled to estimate the population variance when ________________.    A. The population variances are known and equal B. The population means are known C. The population variances are assumed unequal and unknown 22.When testing the difference between two dependent population means, the test statistic is based.
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  101.LongLast Inc. produces car batteries. The mean life of these batteries is 60 months. The distribution of the battery life closely follows the normal probability distribution with a standard deviation of eight months. As a part of its testing program, LongLast tests a sample of 25 batteries. What proportion of.
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  88.Making generalized statements about a population based on sample information is called _________________.    89.A 95% confidence interval implies that about 95 out of 100 similarly constructed intervals will include the _____________ being estimated.    90.For a sampling distribution of means with a known population standard deviation, ______% of the means would be between.
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  26.What kind of distribution is the t distribution?    A. Continuous B. Discrete C. Subjective D. A z distribution 27.How is the t distribution similar to the standard z distribution?    A. Both are discrete distributions. B. Both are skewed distributions. C. Both are families of distributions. D. Both are continuous distributions. 28.A random sample of 20 items is selected from a population. When computing a confidence interval for the.
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  56.A survey of 50 retail stores revealed that the average price of a microwave was $375 with a sample standard deviation of $20. Assuming the population is normally distributed, what is the 99% confidence interval to estimate the true cost of the microwave?    A. $367.42 to $382.58 B. $315.00 to $415.00 C. $323.40 to $426.60 D. $335.82 to.
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  73.Sampling from a population may be preferred, because studying all the items in a population may be too ____________.    74.Sampling from a population may be preferred because, contacting or listing the entire population would be too ___________ consuming.    75.Sampling is required when crash testing cars because the products are __________.    76.A total of.
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  67.The critical t statistic for an alternative hypothesis, H1: µ > 30, a 1% level of significance, and a sample size of 8 is __________.    68.The critical t statistic for the alternative hypothesis, H1: µ < 12, a 0.005 level of significance, and a sample size of 20 is ______.    69.As the.
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  123.Approximately 25% of tourists going to Atlantic City to gamble spend more than $500. The Atlantic City Chamber of Commerce wants to update this percentage. For the new study, the estimate should be within 1% of the population proportion, with a 90% confidence level. What is the necessary sample size?    124.A.
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  56.A hypothesis regarding the weight of newborn infants at a community hospital is that the mean is 6.6 pounds. A sample of seven infants is randomly selected and their weights at birth are recorded as 9.0, 7.3, 6.0, 8.8, 6.8, 8.4, and 6.6 pounds. What is the sample variance?    A. 1.177 B. 6.6 C. 1.385 D. 7.6 57.A hypothesis.
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  11.If the null hypothesis is µµ≥ 200, then a two-tail test is being conducted.    12.A p-value is a probability.    13.A p-value is the same as a stated significance level.    14.Assuming that the null hypothesis is true, a p-value is the probability of observing a sample value greater than and/or less than an observed.
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  36.A manufacturer of automobile transmissions uses two different processes. Management ordered a study of the production costs to see if there is a difference between the two processes. A summary of the findings is shown next.  What is the critical value of F at the 5% level of significance?    A. 19.45 B. 3.00 C. 4.41 D. 4.38 37.A manufacturer of.
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  36.When a confidence interval for a population mean is constructed from sample data, __________.    A. we can conclude that the population mean is in the interval B. we can conclude that the population mean is not in the interval C. we can conclude, for an infinite number of samples and corresponding confidence intervals, that the population.
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  41.The results of a mathematics placement exam at two different campuses of Mercy College follow:  Given that the two population standard deviations are known, what is the p-value?    A. 1.0 C. 0.05 D. 0.95 42.Accounting procedures allow a business to evaluate their inventory costs based on two methods: LIFO (Last In First Out) or FIFO (First In First.
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  16.A null hypothesis makes a claim about a __________.    A. Population parameter B. Sample statistic C. Sample mean D. Type II error 17.Define the level of significance.    A. It is the probability of a Type II error. B. It is the probability of a Type I error. C. It is a z value of 1.96. D. It is the beta error. 18.The mean length of a candy bar.
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  16.An Fstatistic is __________.    A. A ratio of two means B. A ratio of two variances C. The difference between three means D. A population parameter 17.What distribution does the F distribution approach as the sample size increases?    A. Binomial B. Normal C. Poisson D. Exponential 18.Which statement is correct about the F distribution?    A. Cannot be negative B. Cannot be positive C. Is the same as the t distribution D. Is the same as the.
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  94.The American Auto Association reports that the mean price per gallon of regular gasoline is $3.10, with a population standard deviation of $0.20. Assume a random sample of 16 gasoline stations is selected and their mean cost for regular gasoline is computed. What is the standard error of the mean.
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  109.A population consists of 12 values. How many samples of size six are possible?    110.A university has 1,000 computers available for students to use. Each computer has a 250-gigabyte hard drive. The university wants to estimate the space occupied on the hard drives. A random sample of 100 computers showed a.
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  78.A sample mean is a _______________ estimate of the population mean.    79.To calculate the sample size required to estimate a population mean, we must know or estimate the ______________ of the population distribution.    80.When estimating a population mean with a confidence interval, a smaller margin of error requires a _________ sample size.    81.A(n).
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  77.A statement about the value of a population parameter is called a ________________.    78.The alternate hypothesis can be accepted only if the null hypothesis is shown to be _________.    79.A manufacturer claims that less than 1% of all its products do not meet the minimum government standards. A survey of 500 products.
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  83.If the size of a sample equals the size of the population, the sampling error is ________.    84.The process of making statements about a population based on a sample from the population is called _______________.    85.A characteristic of a population is called a ______________.    86.The size of the standard deviation of the sampling.
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  46.A university surveyed recent graduates of the English Department for their starting salaries. Four hundred graduates returned the survey. The average salary was $25,000. The population standard deviation is $2,500. A 95% confidence interval is constructed. What does the confidence interval mean?    A. The population mean is in the interval. B. The population mean.
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  11.If we want to determine which treatment means differ, we compute a confidence interval for the difference between each pair of means.    12.When a blocking effect is included in an ANOVA, the result is a larger error sum of squares.    13.When a blocking effect is included in an ANOVA, the analysis is.
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  66.A survey of an urban university (population of 25,450) showed that 750 of 1,100 students sampled attended a home football game during the season. Using the 90% level of confidence, what is the confidence interval for the proportion of students attending a football game?    A. [0.7510, 0.8290] B. [0.6591, 0.7045] C. [0.6659, 0.6941] D. [0.6795, 0.6805] 67.A survey of.
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  63.When the population standard deviations are unknown, the purpose of pooling the sample variances when testing the difference between two populations is to ___________.    64.If we are testing for the difference between two population means and assume that the two populations have equal and unknown standard deviations, the standard deviations are.
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  1.A point estimate is a single value used to estimate a population parameter.    2.A point estimate is a range of values used to estimate a population parameter.    3.An interval estimate is a single value used to estimate a population parameter.    4.An interval estimate is a range of values used to estimate a population.
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