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Which of the following is a true statement? (A) The area under the standard normal curve between o and 2 is twice the area between \(\mathrm{o}\) and \(1 .\) (B) The area under the standard normal curve between o and 2 is half the area between -2 and 2 . (C) For the standard normal curve, the interquartile range is approximately 3 (D) For the standard normal curve, the range is 6 . (E) For the standard normal curve, the area to the left of 0.1 is the same as the area to the right of \(0.9 .\)

Which of the following is a true statement? (A) The larger the sample, the larger the spread in the sampling distribution is. (B) Bias relates to the spread of a sampling distribution. (C) Provided that the population size is significantly greater than the sample size, the spread of the sampling distribution does not depend on the population size. (D) Sample parameters are used to make inferences about population statistics. (E) Statistics from smaller samples have less variability.

Which of the following is a true statement? (A) The sampling distribution of \(\hat{p}\) has a mean equal to the population proportion \(p\). (B) The sampling distribution of \(\hat{p}\) has a standard deviation equal to \(\sqrt{n p(1-p)}\) (C) The sampling distribution of \(\hat{p}\) has a standard deviation that becomes larger as the sample size becomes larger. (D) The sampling distribution of \(\hat{p}\) is considered close toour sample is clearly less than \(10 \%\) of all butterfly larvae normal provided that \(n \geq 30\). (E) The sampling distribution of \(\hat{p}\) is always close to normal.

Assume the given distributions are approximately normal. A trucking firm determines that its fleet of trucks averages a mean of 12.4 miles per gallon with a standard deviation of 1.2 miles per gallon on cross-country hauls. What is the probability that one of the trucks averages fewer than 10 miles per gallon? (A) \(P(z<-2.4)\) (B) \(P(z<-2)\) (C) \(P(z<10)\) (D) \(P\left(z<\frac{10}{1.2}\right)\) (E) \(P\left(z<\frac{12.4}{1.2}\right)\)

In a school of 25 oo students, the students in an AP Statistics class are planning a random survey of 100 students to estimate the proportion who would rather drop lacrosse than band during this time of severe budget cuts. Their teacher suggests instead to survey 200 students in order to (A) reduce bias. (B) reduce variability. (C) increase bias. (D) increase variability. (E) make possible stratification between lacrosse and band.

Which of the following is an incorrect statement? (A) The sampling distribution of \(\bar{x}\) has mean equal to the population mean \(\mu\) even if the population is not normally distributed. (B) The sampling distribution of \(\bar{x}\) has standard deviation \(\frac{\sigma}{\sqrt{n}}\) even if the population is not normally distributed. (C) The sampling distribution of \(\bar{x}\) is normal if the population has a normal distribution. (D) When \(n\) is large, the sampling distribution of \(\bar{x}\) is approximately normal even if the population is not normally distributed. (E) The larger the value of the sample size \(n\), the closer the standard deviation of the sampling distribution of \(\bar{x}\) is to the standard deviation of the population.

Assume the given distributions are approximately normal. An electronic product takes an average of 3.4 hours to move through an assembly line. If the standard deviation is 0.5 hours, what is the probability that an item will take between 3 and 4 hours to move through the assembly line? (A) \(P(3

Which of the following is the best reason that the sample maximum is not used as an estimator for the population maximum? (A) The sample maximum is biased. (B) The sampling distribution of the sample maximum is not binomial. (C) The sampling distribution of the sample maximum is not normal. (D) The sampling distribution of the sample maximum has too large a standard deviation. (E) The sample mean plus three sample standard deviations gives the best estimate for the population maximum.

The distribution of ages of people who died last year in the United States is skewed left. What happens to the sampling distribution of sample means as the sample size goes from \(n\) \(=50\) to \(n=200 ?\) (A) The mean gets closer to the population mean, the standard deviation stays the same, and the shape becomes more skewed left. (B) The mean gets closer to the population mean, the standard deviation becomes smaller, and the shape becomes more skewed left. (C) The mean gets closer to the population mean, the standard deviation stays the same, and the shape becomes closer to normal. (D) The mean gets closer to the population mean, the standard deviation becomes smaller, and the shape becomes closer to normal. (E) The mean stays the same, the standard deviation becomes smaller, and the shape becomes closer to normal.

Assume the given distributions are roughly normal. The mean income per household in a certain state is \(\$ 9500\) with a standard deviation of \(\$ 1750 .\) The middle \(95 \%\) of incomes are between what two values? (A) \(9500 \pm 1.645(1750)\) (B) \(9500 \pm 1.96(1750)\) (C) \(9500 \pm 1.645\left(\frac{1750}{2}\right)\) (D) \(9500 \pm \frac{1750}{1.645}\) (E) \(9500 \pm \frac{1750}{1.96}\)