A) parameter and, therefore, a fixed characteristic of a data set. B) statistic and, therefore, a random variable. C) statistic and, therefore, a round variable. D) parameter and, therefore, a random variable. A) parameter and, therefore, a fixed characteristic of a data set. B) statistic and, therefore, a random variable. C) statistic and, therefore, a round variable. D) parameter and, therefore, a random variable.

Exam 9: Confidence Intervals Based on a Single Sample

Psychologists wish to evaluate the consistency of a standardized behavioral test.The test is designed to have a variance of 225.Twenty randomly sampled tests yield a variance of 240.Assuming the underlying population is normal, what is a 90% confidence interval for the variance of this test?

(Multiple Choice)

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Question 21

An exit poll is conducted to estimate the proportion of voters who chose candidate A over candidate B.Out of 40 people surveyed, 12 indicated that they had voted for candidate A.What is a 95% confidence interval for the proportion of voters who chose candidate A?

(Multiple Choice)

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Question 22

A rule used to produce a point estimate of a population parameter is called a(n):

(Multiple Choice)

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Question 23

What critical value would be appropriate for a 98% confidence interval on a mean where σ is unknown if the sample size is 10 and the population is normally distributed?

(Multiple Choice)

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Question 24

A random sample of 400 Texas A&M students was taken recently to determine an estimate of the proportion of all Texas A&M students who had attended at least three home football games.The estimate revealed that this proportion was between 0.372 and 0.458.Given this information, we can determine that the confidence coefficient was approximately:

(Multiple Choice)

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Question 25

Fat-tailed sheep are a common sight in the Near East.Some fat-tailed sheep are spotted, whereas others are solid colored.Of those that have a solid color, a small percentage of these fat-tailed sheep are completely black.If we randomly observe 18 black fat-tailed sheep out of a total of 218 sheep, what interval can we be 90% certain contains the population proportion of black fat-tailed sheep?

(Multiple Choice)

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Question 26

A random sample of 33 pitches from a pitching machine set to throw at 80 mph yields an average speed of 79.25 mph.If we know that the standard deviation of speed from this machine is 2.22 mph, what is a 98% confidence interval for the mean pitch speed?

(Multiple Choice)

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Question 27

A _______________ for a population parameter is an interval of values constructed so that, given a specified degree of confidence, the value of the population parameter lies within this interval.

(Multiple Choice)

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Question 28

To budget for the coming year, a community hospital must estimate the proportion of treated patients who will not be able to make payment in full.In a random sample of 2568 patients treated in the previous year, 381 failed to make payment in full.What is an 80% confidence interval for the proportion of patients who will not make full payment to the hospital?

(Multiple Choice)

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Question 29

Prior to the 1999-2000 NBA season, rules were changed in an effort to increase scoring and make basketball games more exciting.Previously, the league averaged 183.2 points per games.A random sample of 25 games played during December 1999 had a sample mean of 195.88 points per game, with a sample standard deviation of 20.27 points per game.What is a 95% confidence interval for the mean number of points per game after the rule change? Does this interval provide evidence of an increase in the average number of points per game?

(Multiple Choice)

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Question 30

The MVUE (minimum variance unbiased estimator) for a parameter:

(Multiple Choice)

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Question 31

Sales from a chain of computer stores are normally distributed, with an average monthly sales volume of $280,560.Estimating the amount of monthly variability in sales is of interest to help anticipate normal income fluctuations.A random sample of 8 months' sales data yields a standard deviation of $10,423.What is a 98% confidence interval for the standard deviation of monthly sales volume?

(Multiple Choice)

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Question 32

A recent survey indicates that the proportion of season ticket holders for the Virginia Tech football team who renew their seats is approximately 0.80.Using this information, the sample size that is needed to estimate the true proportion who plan to renew their seats using 95% confidence with an error bound of 0.025 is:

(Multiple Choice)

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Question 33

Why is a point estimate alone insufficient for providing a probabilistic estimate of a parameter?

(Multiple Choice)

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Question 34

In a sample of 200 items, 12 items are defective.What is the point estimate of the population proportion that is defective?

(Multiple Choice)

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Question 35

When we use estimation to determine the value of a parameter, we always use random sampling, rather than convenience sampling or judgment sampling, because random sampling:

(Multiple Choice)

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Question 36

A biased estimator may be preferable to an unbiased estimator if:

(Multiple Choice)

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Question 37

A random sample of size 25 taken from a normally distributed population resulted in a sample standard deviation of 0.93054.A 99% confidence interval for the population variance would be:

(Multiple Choice)

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Question 38

An estimator is a:

(Multiple Choice)

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Question 39

What is t.01 if the distribution has 15 degrees of freedom?

(Multiple Choice)

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Question 40

Showing 21 - 40 of 51

Psychologists wish to evaluate the consistency of a standardized behavioral test.The test is designed to have a variance of 225.Twenty randomly sampled tests yield a variance of 240.Assuming the underlying population is normal, what is a 90% confidence interval for the variance of this test?

An exit poll is conducted to estimate the proportion of voters who chose candidate A over candidate B.Out of 40 people surveyed, 12 indicated that they had voted for candidate A.What is a 95% confidence interval for the proportion of voters who chose candidate A?

A rule used to produce a point estimate of a population parameter is called a(n):

What critical value would be appropriate for a 98% confidence interval on a mean where σ is unknown if the sample size is 10 and the population is normally distributed?

A random sample of 33 pitches from a pitching machine set to throw at 80 mph yields an average speed of 79.25 mph.If we know that the standard deviation of speed from this machine is 2.22 mph, what is a 98% confidence interval for the mean pitch speed?

A _______________ for a population parameter is an interval of values constructed so that, given a specified degree of confidence, the value of the population parameter lies within this interval.

The MVUE (minimum variance unbiased estimator) for a parameter:

Why is a point estimate alone insufficient for providing a probabilistic estimate of a parameter?

In a sample of 200 items, 12 items are defective.What is the point estimate of the population proportion that is defective?

When we use estimation to determine the value of a parameter, we always use random sampling, rather than convenience sampling or judgment sampling, because random sampling:

A biased estimator may be preferable to an unbiased estimator if:

A random sample of size 25 taken from a normally distributed population resulted in a sample standard deviation of 0.93054.A 99% confidence interval for the population variance would be:

An estimator is a:

What is t.01 if the distribution has 15 degrees of freedom?

Why Study Statistics

An Introduction to Statistics and Statistical Inference

Tables and Graphs for Summarizing Data

Numerical Summary Measures

Probability

Random Variables and Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions

Hypothesis Tests Based on a Single Sample

Confidence Intervals and Hypothesis Tests Based on Two Samples or Treatments

The Analysis of Variance

Correlation and Linear Regression

Categorical Data and Frequency Tables

Nonparametric Statistics

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