The owner of a fish market has an assistant who has determined that the

Question 1

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As the sample size increases, the effect of an extreme value on the sample mean becomes smaller.

 Question 2

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The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed, with mean of 3.2 pounds and standard deviation of 0.8 pound. If a sample of 25 fish yields a mean of 3.6 pounds, what is the Z-score for this observation?

 Question 3

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Which of the following is TRUEabout the sampling distribution of the sample mean?

 Question 4

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If the population distribution is unknown, in most cases the sampling distribution of the mean can be approximated by the normal distribution if the samples contain at least 30 observations.

 Question 5

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The amount of time it takes to complete an examination has a skewed-left distribution with a mean of 65 minutes and a standard deviation of 8 minutes. If 64 students were randomly sampled, the probability that the sample mean of the sampled students exceeds 71 minutes is approximately 0.

 Question 6

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A sampling distribution is a probability distribution for a statistic.

 Question 7

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The standard error of the mean for a sample of 100 is 30. In order to cut the standard error of the mean to 15, we would

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If the amount of gasoline purchased per car at a large service station has a population mean of $15 and a population standard deviation of $4 and it is assumed that the amount of gasoline purchased per car is symmetric, there is about a 68% chance that a random sample of 16 cars will have a sample mean between $14 and $16.

 Question 9

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A university dean is interested in determining the proportion of students who receive some sort of financial aid. Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of them are receiving financial aid. The 95% confidence interval for pis 0.59 ± 0.07. Interpret this interval.

 Question 10

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A major department store chain is interested in estimating the average amount its credit card customers spent on their first visit to the chain's new store in the mall. Fifteen credit card accounts were randomly sampled and analyzed with the following results: the sample mean = $50.50 and sample variance = 400. Assuming the distribution of the amount spent on their first visit is approximately normal, what is the shape of the sampling distribution of the sample mean that will be used to create the desired confidence interval for µ (mu)?

 Question 11

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A major department store chain is interested in estimating the average amount its credit card customers spent on their first visit to a new store. Fifteen credit card accounts were randomly sampled and analyzed with the following results: sample mean=$50.50 and sample variance=121. Construct a 95% confidence interval for the average amount its credit card customers spent on their visit to the chain's new store in the mall assuming that the amount spent follows a normal distribution (that is, the sample variance equals the population variance).

 Question 12

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As an aid to the establishment of personnel requirements, the director of a hospital wishes to estimate the mean number of people who are admitted to the emergency room during a 24-hour period. The director randomly selects 64 different 24-hour periods and determines the number of admissions for each. For this sample, the sample mean=19.8 and the sample variance =25. Estimate the mean number of admissions per 24-hour period with a 95% confidence interval.

 Question 13

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The tdistribution

 Question 14

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A sample size of 5 provides a sample mean of 9.6. If the population variance is known to be 5 and the population distribution is assumed to be normal, the lower limit for a 92% confidence interval is 7.85.

 Question 15

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A university dean is interested in determining the proportion of students who receive some sort of financial aid. Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of them are receiving financial aid. If the dean wanted to estimate the proportion of all students receiving financial aid to within 3% with 99% reliability, how many students would need to be sampled?

 Question 16

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A librarian asked his assistant for an estimate of the mean number of books checked out each day. The assistant estimated from 740 to 920 books per day. What is an efficient, unbiased point estimate of the number of books checked out each day?

 Question 17

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If a test of hypothesis has a Type I error probability, ? = 0.01, we mean

 Question 18

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If the Type I error, ? for a given test is to be decreased, then for a fixed sample size:

 Question 19

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If the p-value is less than ? in a two-tailed test, then:

 Question 20

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Which of the following would be an appropriate null hypothesis?

 Question 21

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A is a numerical quantity computed from the data of a sample and is used in reaching a decision on whether or not to reject the null hypothesis.

 Question 22

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Suppose we wish to test the null hypothesis H₀: ? ? 47 versus H₁: ? > 47. What will result if we conclude that the mean is greater than 47 when its true value really is 52?

 Question 23

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The symbol for the power of a statistical test is

 Question 24

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Which of the following would be an appropriate alternative hypothesis?

 Question 25

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The power of a test is measured by its capability of