review +

Use Scenario 6-9. What is the probability that the total weight of three randomly selected grapefruits is more than 3.4 pounds? nearly 0 0.0274 0.1335 0.2514 0.2611

0.0274

Use Scenario 6-3. Which of the following is the standard deviation of X? 1 0.6325 0.4472 0.4 The answer cannot be computed from the information given.

0.4472

Sulé's job is just a few bus stops away from his house. While it can be faster to take the bus to work, it's more variable, because of variations in traffic. He estimates that the commute time to work by bus is approximately Normally distributed with a mean of 12 minutes and a standard deviation of 4 minutes. The commute time if he walks to work is also approximately Normally distributed with a mean of 16 minutes with a standard deviation of 1 minute. A. 0.8340 B. 0.8485 C. 0.8980 D. 0.9756 E. 0.9896

0.8340

Use Scenario 5-3. The probability that at least one of the next three babies is a boy is 0.125. 0.333. 0.667. 0.750. 0.875.

0.875.

Use Scenario 3-8. On average, how far are the predicted y-values from the actual y-values? 25.55 5.392 6.75133 0.697 Cannot be determined without the original data.

25.55

You want to take an SRS of 50 of the 816 students who live in a dormitory on campus. You label the students 001 to 816 in alphabetical order. In the table of random digits you read the entries. 95592 94007 69769 33547 72450 16632 81194 14873 Use Scenario 4-4. The first three students in your sample have labels 955, 929, 400. 400, 769, 769. 559, 294, 007. 929, 400, 769. 400, 769, 335.

400, 769, 335.

Which of the following best describes the correlation r? The average of the products of each of the X and Y values for each point The average of the products of the standardized scores of X and Y for each point. The average of the squared products of the standardized scores of X and Y for each point. The average of the differences between each X value and each Y value. The average perpendicular distance between each data point and the least-squares regression line.

The average of the products of the standardized scores of X and Y for each point.

Which of the following statement is not supported by the information in the scatter plot? About half the European countries consume more wine per person than any of thenon-European countries. On average, the non-European countries drink less wine and have more heart attacks. The four countries with the highest rates of wine consumption are all European. The correlation between wine consumption and heart disease deaths is equally strong in European countries and non-European countries. The country with the highest heart disease death rate is in Europe.

The correlation between wine consumption and heart disease deaths is equally strong in European countries and non-European countries.

Which of the following is correct? The correlation r is the slope of the least-squares regression line. The square of the correlation is the slope of the least-squares regression line. The square of the correlation is the proportion of the data lying on the least-squares regression line. The mean of the residuals from least-squares regression is 0. The sum of the squared residuals from the least-squares line is 0.

The mean of the residuals from least-squares regression is 0.

Based on these data, which of the following statements is correct? These data are consistent with the idea that there is a link between high blood pressure and death from cardiovascular disease. The mortality rate (proportion of deaths) for men with high blood pressure is 5 times that of men with low blood pressure. These data probably understate the link between high blood pressure and death from cardiovascular disease, because men will tend to understate their true blood pressure. Although there were more deaths in the high blood pressure group, this is expected, because there were 1500 more men in that group. All of the above.

These data are consistent with the idea that there is a link between high blood pressure and death from cardiovascular disease.

Which of the following statements is false? Some owners let their pets ride in more than one place in the car. A majority of owners allow their pets to ride in the front passenger seat. The most common place dogs ride is in the back seat. The vertical scale of this graph exaggerates the difference between the percentage who let their dogs ride in the driver's lap versus a passenger's lap. These data could also be presented in a pie chart.

These data could also be presented in a pie chart.

A simple random sample is any sample selected by using chance. any sample that gives every individual the same chance to be selected. a sample that gives every possible sample of the same size the same chance to be selected. a sample that selects equal numbers of individuals from each stratum. a sample that contains the same percent of each subgroup in the population.

a sample that gives every possible sample of the same size the same chance to be selected.

Use Scenario 4-6. Suppose half of the 8:30 students are randomly allocated to the treatment group (two cups of coffee), the other half to the control group (two cups of decaf). In addition, half of the 9:30 students are randomly allocated to the treatment group, the other half to the control group. This is an example of a voluntary response study. stratified sampling procedure. matched pairs design. completely randomized design. block design.

block design.

When drawing a histogram it is important to have a separate class interval for each observation to get the most informative plot. make sure the heights of the bars exceed the widths of the class intervals so that the bars are true rectangles. label the vertical axis so the reader can determine the counts or percent in each class interval. leave large gaps between bars. This allows room for comments. scale the vertical axis according to the variable whose distribution you are displaying.

label the vertical axis so the reader can determine the counts or percent in each class interval.

A 1992 Roper poll found that 22% of Americans say that the Holocaust may not have happened. The actual question asked in the poll was "Does it seem possible or impossible to you that the Nazi extermination of the Jews never happened?" and 22% responded possible. The results of this poll cannot be trusted because undercoverage is present. Obviously, those people who did not survive the Holocaust could not be in the poll. the question is worded in a confusing manner. we do not know who conducted the poll or who paid for the results. nonresponse is present. Many people will refuse to participate, and those who do will be biased in their opinions. the question is clearly biased in the direction of a "possible" answer.

the question is worded in a confusing manner.

Use Scenario 6-2. Which of the following is the standard deviation of X? A. $1.00 $1.35 $1.41 $1.78 $2.00

$1.41

Use Scenario 5-13. If two students are selected at random, what is the probability that neither of them has a dog or a cat? 0.37 0. 540 0. 548 0.655 0.74

0. 548

Use Scenario 5-8. Given that a student who ate breakfast is selected, what is the probability that he is male? 0.32 0.40 0.50 0.64 0.80

0.64

Use Scenario 6-1. The probability of at least one tail is 0.2500. 0.3125. 0.6875. 0.9375. none of these.

0.9375.

Use Scenario 6-16. If the reporter asks adults on the street at random, what is the probability that he will find a Democrat by the time he has stopped three people? A. 0.936 B. 0.216 C. 0.144 D. 0.096 E. 0.064

A. 0.936

Use Scenario 6-10. What is the standard deviation of Z? A. 1.20 B. 1.30 C. 1.45 D. 1.70 E. 2.89

A. 1.20

"Insert tab A into slot B" is something you might read in the assembly instructions for pre-fabricated bookshelves. Suppose that tab A varies in size according to a Normal distribution with a mean of 30 mm. and a standard deviation of 0.5 mm., and the size of slot B is also Normally distributed, with a mean of 32 mm. and a standard deviation of 0.8 mm. The two parts are randomly and independently selected for packaging. What is the probability that tab A won't fit into slot B? A. 0.0007 B. 0.0170 C. 0.0618 D. 0.9382 E. 0.9830

B. 0.0170

Use Scenario 6-17. You're going to give up and call a tow truck if you don't find jumper cables by the time you've asked 10 people. A. 0.8251 B. 0.1749 C. 0.1344 D. 0.0333 E. 0.0280

B. 0.1749

Use Scenario 6-5. The standard deviation of the number of customers that make a purchase during the first hour that the store is open is A. 0.2. B. 1.4. C. 2.0. D. 3.0. E. 4.0.

B. 1.4.

Use Scenario 4-4. Another correct choice of labels for the 816 students is 000 to 816 in alphabetical order. still 001 to 816, but in order of the students' ID numbers. 000 to 815 in alphabetical order. Both (B) and (C) are correct. All of (A), (B), and (C) are correct.

Both (B) and (C) are correct.

Which of the following statements describes what the standard deviation of residuals for a regression equation can be used for? I. It describes the typical vertical distance between an observed data point and the regression line. II. It evaluate whether a linear model is appropriate for a set of data. III. It measures the overall precision of predictions made using the regression equation. I only II only III only Both I and II Both I and III

Both I and III

Simple random sampling reduces bias resulting from poorly worded questions. offsets bias resulting from undercoverage and nonresponse. reduces bias resulting from the behavior of the interviewer. reduces variability. None of the above.

None of the above.

The principle reason for the use of random assignment in designing experiments is that it distinguishes a treatment effect from the effects of confounding variables. allows double-blinding. reduces sampling variability. creates approximately equal groups for comparison. eliminates the placebo effect.

creates approximately equal groups for comparison.

The principle reason for the use of controls in designing experiments is that it distinguishes a treatment effect from the effects of confounding variables. allows double-blinding. reduces sampling variability. creates approximately equal groups for comparison. eliminates the placebo effect.

distinguishes a treatment effect from the effects of confounding variables.

A stack of four cards contains two red cards and two black cards.not replace the first card selected before selecting the second card. Consider the events A = the first card selected is redB = the second card selected is red The events A and B are independent and disjoint. not independent, but disjoint. independent, not disjoint not independent, not disjoint. independent, but we can't tell it's disjoint without further information.

not independent, not disjoint.

The reason that blocking (as in a randomized block design) is sometimes used in experimentation is to prevent the placebo effect. allow double blinding. eliminate lurking variables eliminate the need for random assignment. reduce variability arising from random assignment.

reduce variability arising from random assignment.

Twelve people who suffer from chronic fatigue syndrome volunteer to take part in an experiment to see if shark fin extract will increase one's energy level. Eight of the volunteers are men, and four are women. Half of the volunteers are to be given shark fin extract twice a day, and the other half are to be given a placebo twice a day. We wish to make sure that four men and two women are assigned to each of the treatments, so we decide to use a block design with the men forming one block and the women the other. A block design is appropriate in this experiment if we want to be able to compare effects on energy level in men and women. we believe men and women will respond differently to treatments. gender equity is an important legal consideration in this study. we want the conclusions to apply equally to men and women. all of the above.

we believe men and women will respond differently to treatments.

A box has 10 tickets in it, two of which are winning tickets. You draw a ticket at random. If it's a winning ticket, you win. If not, you get another chance, as follows: your losing ticket is replaced in the box by a winning ticket (so now there are 10 tickets, as before, but 3 of them are winning tickets). You get to draw again, at random. Which of the following are legitimate methods for using simulation to estimate the probability of winning? I. Choose, at random, a two-digit number. If the first digit is 0 or 1, you win on the first draw; If the first digit is 2 through 9, but the second digit is 0, 1, or 2, you win on the second draw. Any other two-digit number means you lose. II. Choose, at random, a one-digit number. If it is 0 or 1, you win. If it is 2 through 9, pick a second number. If the second number is 8, 9, or 0, you win. Otherwise, you lose.III. Choose, at random, a one-digit number. If it is 0 or 1, you win on the first draw. If it is 2, 3, or 4, you win on the second draw; If it is 5 through 9, you lose. I only II only III only I and II I, II, and III

I and II

The first sentence in Henry James's novel The Turn of the Screw has 62 words. for the lengths of those words is 1,2,3.5,6,12. According to the 1.5 x IQR rule for identifying outliers, does this distribution have any outliers? No, there are no outliers. Yes, there is at least on high outlier but no low outliers. Yes, there is at least one low outliers, but no high outliers. Yes, there is at least one high and one low outlier. There is not enough information given to determine if there are any outliers.

No, there are no outliers.

Use Scenario 3-2. Do these data provide strong evidence that drinking wine actually causes a reduction in heart disease deaths? Yes. The strong straight-line association in the plot shows that wine has a strong effect on heart disease deaths. No. Countries that drink lots of wine may differ in other ways from countries that drink little wine. We can't be sure the wine accounts for the difference in heart disease deaths. No. r does not equal -1. No. The plot shows that differences among countries are not large enough to be important. No. The plot shows that deaths go up as more alcohol from wine is consumed.

No. Countries that drink lots of wine may differ in other ways from countries that drink little wine. We can't be sure the wine accounts for the difference in heart disease deaths.

A basketball player shoots 8 free throws during a game. The sample space for counting the number she makes is S = any number between 0 and 1. S = whole numbers 0 to 8. S = whole numbers 1 to 8. S = all sequences of 8 hits or misses, like HMMHHHMH. S = {HMMMMMMM, MHMMMMMM, MMHMMMMM, MMMHMMMM, MMMMHMMM, MMMMMHMM, MMMMMMHM, MMMMMMMH}

S = whole numbers 0 to 8.

Use Scenario 4-7. If the farmer had fed Kent pellets to an SRS of 5 pigs from litter A and an SRS of 5 pigs from litter B, with the remaining 10 pigs getting Moormans pellets, then he would have been using a systematic random sample. a convenience sample. a matched-pairs design. a block design. a completely randomized design.

a block design.