The following questions are the type your teacher might ask you on a quiz or a test. Practice with these in order to improve your performance on class tests.

Multiple-Choice Questions

If the Federal Reserve followed an easy money policy, it would

a. increase the money supply to lower interest rates.

b. increase the money supply to raise interest rates.

c. decrease the money supply to lower interest rates.

d. decrease the money supply to raise interest rates.

Suppose that you want to perform a hypothesis test based on a simple random paired sample to compare the means of two populations. For each part, decide whether you would use the paired t-test, the paired Wilcoxon signed-rank test, or neither of these tests. Preliminary data analyses of the sample of paired differences suggest that the distribution of the paired-difference variable is a. approximately normal. b. highly skewed; the sample size is 20. c. symmetric bimodal.

In 2014, Rouse & Sons, a small environmental-testing firm, performed 12,200 radon tests for $290 each and 16,400 lead tests for$240 each. Because newer homes are being built with lead-free pipes, lead-testing volume is expected to decrease by 10% next year. However, awareness of radon-related health hazards is expected to result in a 6% increase in radon-test volume each year in the near future. Jim Rouse feels that if he lowers his price for lead testing to $230 per test, he will have to face only a 7% decline in lead-test sales in 2015.

1. Prepare a 2015 sales budget for Rouse & Sons assuming that Rouse holds prices at 2014 levels.

2. Prepare a 2015 sales budget for Rouse & Sons assuming that Rouse lowers the price of a lead test to$230. Should Rouse lower the price of a lead test in 2015 if the company’s goal is to maximize sales revenue?

construct a scatterplot, and.find the value of the linear correlation coefficient r. Also find the P-value or the critical values of r Use a significance level of $\alpha$ = 0.05. Determine whether there is sufficient evidence to support a claim of a linear correlation between the two variables. Listed below are combined city- highway fuel economy ratings (in mi/ gal) for different cars. The old ratings are based on tests used before 2008 and the new ratings are based on tests that went into effect in 2008. Is there sufficient evidence to conclude that there is a linear correlation between the old rati ngs and the new ratings? What do the data suggest about the old ratings?

$$\begin{array} { | c | c | c | c | c | c | c | c|c|c|c|c|} \hline \text { Old } & { 16 } & { 27 } & { 17 } & { 33 } & { 28 } & { 24 } &18&22&20&29&21\\ \hline \text { New } & { 15 } & { 24 } & { 15 } & { 29 } & { 25 } & { 22 }&16&20&18&26&19 \\ \hline \end{array}$$

Circle the correct bold term in parentheses to complete each sentence.

Chris had been a heavy alcohol drinker all of his adult life. His wife noticed worsening yellow discoloration of the whites of his eyes and skin. After a physical examination and blood tests, his family physician told him his (colon, skin, liver) was diseased. The yellow discoloration was (jaundice, melena, flatus), and his condition was (cheilosis, cirrhosis, steatorrhea).

It is known that 2 % of the population has a certain allergy. A test correctly identifies people who have the allergy 98 % of the time. The test correctly identifies people who do not have the allergy 95 % of the time. A website recommends that anyone who tests positive for the allergy should begin taking anti-allergy medication. Fill the two-way table. Determine whether this is a good recommendation. Explain.

The following table shows the least expensive gas prices for three cities on June 1, 2018, as reported by Gasbuddy.com.

a. Assuming the overall level of significance is 0.05, what is the Bonferroni-correct level of significance for the three pairs of cities?

b. Report the sample mean for each city. Which two means are closest to each other?

c. Carry out two-sample t-tests for all three pairs. Instead of using the four-step method, summarize your findings using a table that reports t-test statistics, p-values, and conclusions. Base your conclusions on the Bonferroni-corrected level of significance. Do not assume equal variances. Assume all conditions for two-sample t-tests are met.

Data measured during tests of a centrifugal pump at $2750 \mathrm{~rpm}$ are The flow rate is $65 \mathrm{~gpm}$ and the torque applied to the pump shaft is $6.25 \mathrm{~lbf} \cdot \mathrm{ft}$. Evaluate the total dynamic heads at the pump inlet and outlet, the hydraulic power input to the fluid, and the pump efficiency. Specify the electric motor size needed to drive the pump. If the electric motor efficiency is $85$ percent, calculate the electric power requirement.

The microprocessors manufactured by United Motor Works, which are used in automobiles to regulate fuel consumption, are guaranteed against defects for $20,000 \mathrm{mi}$ of use. Tests conducted in the laboratory under simulated driving conditions reveal that the distances driven in miles before the microprocessors break down are exponentially distributed with probability density function $f(t)=0.00001 e^{-.00001 t}$. What is the probability that a microprocessor selected at random will fail during the warranty period?

Consider the following sample of 10 measurements:

$$\begin{matrix} \text{8.4} & \text{16.9} & \text{15.8} & \text{12.5} & \text{10.3} & \text{4.9} & \text{12.9} & \text{9.8} & \text{23.7} & \text{7.3}\\ \end{matrix}$$

Use these data, the binomial tables or statistical software, and $\alpha=.05$ to conduct each of the following sign tests: $H_{0}: \eta=9$ versus $H_{\mathrm{a}}: \eta \neq 9$

Which samples show unequal variances? Use $\alpha$ = .05 in all tests. Show the critical values and degrees of freedom clearly and illustrate the decision rule.

a. s1 = 5.1, n1 = 11, s2 = 3.2, n2 = 8, two-tailed test

b. s1 = 221, n1 = 8, s2 = 445, n2 = 8, left-tailed test

c. s1 = 67, n1 = 10, s2 = 15, n2 = 13, right-tailed test

Yvonne learns that a refrigerator should be kept at a temperature of no more than $40 ^ { \circ } \mathrm { F }$ but warmer than $32 ^ { \circ } \mathrm { F } .$ a. Write an expression to show the possible range of proper refrigerator temperatures. b. Yvonne tests the temperatures of some refrigerators at an appliance store. The first 4 temperatures are $35 ^ { \circ } , 40 ^ { \circ } , 20 ^ { \circ } ,$ and $45 ^ { \circ }$ . What should the last temperature be if the average of the temperatures is within the proper temperature range?

Tendons are strong elastic fibers that attach muscles to bones. To a reasonable approximation, they obey Hooke's law. In laboratory tests on a particular tendon, it was found that, when a $250$-$\mathrm{g}$ object was hung from it, the tendon stretched $1.23$ cm.
(b) Because of its thickness, the maximum tension this tendon can support without rupturing is $138 \mathrm{~N}$. By how much can the tendon stretch without rupturing, and how much energy is stored in it at that point?

The acceleration of the drag racer is modeled as $\alpha=c_1-c_2 v^2$, where the $v^2$-term accounts for aerodynamic drag and where $c_1$ and $c_2$ are positive constants. If $c_2$ is known (from wind-tunnel tests) to be $5\left(10^{-5}\right) \mathrm{ft}^{-1}$, determine $c_1$ if the final speed is 190 $\mathrm{mi} / \mathrm{hr}$. A drag race is a $1 / 4$-mile straight run from a standing start.