Math assignment help
Question 1  4 points  Save  
As the sample size increases, the effect of an extreme value on the sample mean becomes smaller.  

Question 2  4 points  Save  
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 Zscore for this observation?  

Question 3  4 points  Save  
Which of the following is TRUEabout the sampling distribution of the sample mean?  

Question 4  4 points  Save  
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  4 points  Save  
The amount of time it takes to complete an examination has a skewedleft 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  4 points  Save  
A sampling distribution is a probability distribution for a statistic.  

Question 7  4 points  Save  
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  

Question 8  4 points  Save  
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  4 points  Save  
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  4 points  Save  
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  4 points  Save  
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  4 points  Save  
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 24hour period. The director randomly selects 64 different 24hour 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 24hour period with a 95% confidence interval.  

Question 13  4 points  Save  
The tdistribution  

Question 14  4 points  Save  
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  4 points  Save  
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  4 points  Save  
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  4 points  Save  
If a test of hypothesis has a Type I error probability, ? = 0.01, we mean  

Question 18  4 points  Save  
If the Type I error, ? for a given test is to be decreased, then for a fixed sample size:  

Question 19  4 points  Save  
If the pvalue is less than ? in a twotailed test, then:  

Question 20  4 points  Save  
Which of the following would be an appropriate null hypothesis?  

Question 21  4 points  Save  
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  4 points  Save  
Suppose we wish to test the null hypothesis H_{0}: ? ? 47 versus H_{1}: ? > 47. What will result if we conclude that the mean is greater than 47 when its true value really is 52?  

Question 23  4 points  Save  
The symbol for the power of a statistical test is  

Question 24  4 points  Save  
Which of the following would be an appropriate alternative hypothesis?  

Question 25  4 points  Save  
The power of a test is measured by its capability of  

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