Cars arriving at a drive-through testing center follow a Poisson process with a mean of three minutes between cars at peak hours. Which continuous probability distribution models the time to the next arrival?

a.Binomial distribution

b.Exponential distribution

c.Normal distribution

d.Uniform distribution

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Suppose that the average weight of a dog is 84 pounds with a standard deviation of 4 pounds. What is the z-score for a dog that weighs 90 pounds, assuming that the weight of dogs is normally distributed?

a.1.00

b.1.50

c.2.00

d.2.50

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A sample of n=75 is taken from a normally distributed population with a mean of 87 and a standard deviation of 13. According to the central limit theorem, how would you describe the sampling distribution?

a.Chi-squared with a mean of 13

b.Chi-squared with a mean of 1.50

c.Normal, mean 87, standard deviation 13

d.Normal, mean 87, standard deviation 1.50

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Which of the following is the best explanation for why sampling distributions are used in inferential statistics?

a.Normal sampling distributions can apply to any size sample

b.Normal distributions are easy to calculate even if they are not very accurate

c.Sampling distributions are approximately normal for sufficiently large samples

d.Sampling distributions only apply to simple random samples, which is what we usually use

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A population has a proportion of 22% saying baseball is their favorite sport. A sample of 500 people is taken. What is the standard deviation of the sampling distribution?

a.0.0098

b.0.0185

c.0.022

d.0.22

Which of the following is true about repeating sampling?

a.If the number of samples is greater than 30, the relative frequency distribution will approach the sampling distribution

b.As the number of samples approaches infinity, the relative frequency distribution will approach the sampling distribution

c.As the mean of the samples approaches the mean of the population, the relative frequency distribution will approach the sampling distribution

d.As the mean of the samples approaches 0 with a standard deviation of 1, the relative frequency distribution will approach the sampling distribution

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Suppose that out of 1200 students at your university, 100 are on a break and not taking any classes this semester. Which of the following mathematical expressions describes the mean of the sampling distribution of the proportion of students who are on a break?

a.100 / 1200

b.100 1200

c.(1200 - 100) / 100

d.(1200 - 100) / 1200

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A sample of 125 women is taken and it is determined that the mean height of the sample is 64.5 inches. The standard error is found to be 0.277. Using this value, what would you estimate the standard deviation of the sample to be?

a.0.0248 inches

b.0.277 inches

c.3.1 inches

d.5.77 inches

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As you increase the sample size, what happens to a sampling distribution?

a.It becomes more skewed

b.It becomes more normally distributed

c.It becomes more uniformly distributed

d.It becomes more non-normally distributed

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Four different breeds of dogs are sampled. The characteristics of each sample are listed. Which one has the most reliable estimate of the sample mean?

1. Sample mean 45 pounds, standard deviation 10 pounds, sample size 18
2. Sample mean 5.7 pounds, standard deviation 2.2 pounds, sample size 51
3. Sample mean 33 pounds, standard deviation 4.9 pounds, sample size 65
4. Sample mean 72 pounds, standard deviation 16 pounds sample size 26

a.1

b.2

c.3

d.4

Which of the following statements gives the best definition of a 99% confidence interval for the mean?

a.A 99% confidence interval has a 0.99 probability of containing the sample mean

b.A 99% confidence interval has a 0.99 probability of containing the population mean

c.If repeated samples were taken and the 99% confidence interval was computed for each sample, 99% of the intervals would contain the sample mean

d.If repeated samples were taken and the 99% confidence interval was computed for each sample, 99% of the intervals would contain the population mean

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The t-distribution approximates the normal distribution as you increase which of the following under the t-distribution?

a.Sample size

b.Variables under study

c.Population mean value

d.Number of assumptions

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Applying the Central Limit Theorem, suppose that laptops have a mean weight of 7.5 pounds with a standard deviation of 1.1 pounds. If you take a sample of the weight of 50 different brands of laptop, what would the standard error be?

a.7.5/1.1

b.1.1/50

c.7.5+1.1

d.7.50/50

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Suppose that a women's clothing store wishes to sell dresses of just one size that will fit the average woman. From a scientific study, the company finds that the population standard deviation is two sizes (in number sizes). Assuming that dress size is normally distributed, how would you construct a 95% confidence interval for the population mean when the company takes a sample of 2500 customers and finds the average dress size is 8.5 with a standard deviation of 1.50 sizes?

a.8.5 (1.96)(1.5/2500)

b.8.5 (1.645)(1.5/2500)

c.8.5 (1.96)(1.5/50)

d.8.5 (1.645)(1.5/50)