Statistics (HW 1 2 3)

The preparation time to mail envelopes with a weekly report to all executives in a company has a Normal distribution with a mean of 35 minutes and a standard deviation of 2 minutes. On 95% of such occasions, the mailing preparation takes less than x minutes. What is the value of x?

38.29

The preparation time to mail envelopes with a weekly report to all executives in a company has a Normal distribution with a mean of 35 minutes and a standard deviation of 2 minutes. On 95% of such occasions, the mailing preparation takes less than xminutes. What is the value of x?

38.29

The number of Facebook friends students at a university have are Normally distributed with a mean of 1200 and a standard deviation of 200. What percentage of students has at least 1000 Facebook friends?

84.13%

Malaria is a leading cause of infectious disease and death worldwide. The table below represents the mean number of reported malaria cases (between 1996 and 2006) for each of 10 West African countries, as published in the journal Statistica Neerlandica in 2010. What is the best method to display these data?

Bar graph

A well-known maker of jams and jellies packages its jams in jars labeled "250 milliliters." The process used to fill the jars is known to dispense an amount of jam that is a Normally distributed variable with = 252 milliliters and = 0.9 milliliters. What proportion of jars from this filling process will contain no more than 253.5 milliliters?

0.9522

A tool and die company has been contracted to produce metal castings into which a hole is to be drilled to a diameter of 2.5 centimeters. Because of the variability in the drilling process, the actual diameter of the hole is a Normally distributed variable with a mean of 2.5 centimeters and a standard deviation of 0.1 centimeters. The proportion of castings produced by this process with a hole whose diameter is within 0.2 centimeters of the desired value is

0.9549

In a skills competition involving many different events, two particular contestants were tied on each and every event, always getting the identical score. For the competition, the correlation between the scores of these two contestants is

1

Many residents of suburban neighborhoods own more than one car but consider one of their cars to be the main family vehicle. The age of these family vehicles can be modeled by a Normal distribution with a mean of 2 years and a standard deviation of 6 months. What is the standardized value for a family vehicle that is 3 years and 3 months old?

2.5

The following data are the magnitudes of earthquakes around the world recorded on January 13, 2008.4.1, 4.8, 3.1, 5.3, 5.1, 4.7, 3.0, 2.9, U, 4.6, 3.1, 3.0, U, 2.5.Because of equipment problems, two earthquakes were unrecorded, although it was known that both had a value less than 2.7. The median magnitude of earthquakes on this date is

3.1.

The histogram below represents the height (in inches) of the gold medal-winning high jumps for the Olympic Games up to Sydney 2000. What is approximately the percentage of these winning jumps that were at least 7 feet and1 inch high (85 inches)?

35%

Fill in the blank. The owner of a winery collects data on competing wineries every year. He would like to predict the gross sales (in number of cases) from the size of the wineries (in acres). The variable _______ is the explanatory variable in this study.

Size of the winery

A sample of employees of a large pharmaceutical company has been obtained. The length of time (in months) they have worked for the company was recorded for each employee. A stemplot of these data is shown below. In the stemplot 6|2 represents 62 months. What would be a better way to represent this data set?

Split the stems.

Below is a data set with information on students in a basic statistics class at a local university. Which variable is the label? Hometown Student ID Major GPA

Student ID

Fill in the blank. A study is conducted to determine if one can predict the yield of a crop based on the amount of yearly rainfall. The variable _______ is the response variable in this study.

Yield of the crop

The scatterplot below displays data collected from 20 adults on their age and overall GPA at graduation.The correlation, r, would likely reveal _______ between the two variables.

a weak correlation

Colorectal cancer (CRC) is the third most commonly diagnosed cancer among Americans (with nearly 147,000 new cases), and the third leading cause of cancer death (with over 50,000 deaths annually). Research was done to determine whether there is a link between obesity and CRC mortality rates among African Americans in the United States by county. Below are the results of a least-squares regression analysis from the software StatCrunch. The response variable is ______.

mortality rates

The "direction" in scatterplots refers to the _________ direction.

positive and negative

If you have two quantitative variables, one way to study them is to use a ______.

scatterplot

When trying to explain the relationship between two quantitative variables, it would be best to use a _______.

scatterplot

When making a stemplot, it is appropriate to _______ if the values cover a very small range.

split the stem

Quantitative variables are best displayed using _______.

stemplots

Do heavier cars use more gasoline? To answer this question, a researcher randomly selected 15 cars. He collected data about the weight (in hundreds of pounds) and the mileage (mpg) for each car. From a scatterplot made with the data, a linear model seems appropriate.The percentage of variation in mileage that is accounted for by the linear relationship between mileage and weight is approximately 44%. What is the value of the correlation coefficient between the weight and the mileage of a car? (Round to 3 decimal places).

-0.663

Using the standard Normal distribution tables, what is the area under the standard Normal curve corresponding to Z < 1.1?

0.8643

Using the standard Normal distribution tables, what is the area under the standard Normal curve corresponding to Z > -1.22?

0.8888

A researcher at a large company has collected data on the beginning salary and current salary of 48 randomly selected employees. The least-squares regression equation for predicting their current salary from their beginning salary is = -2532.7 + 2.12x. Mr. Joseph Keller started working for the company earning $22,000. What do you predict his current salary to be?

$44,107.30

The Insurance Institute for Highway Safety publishes data on the total damage suffered by compact automobiles in a series of controlled, low-speed collisions. The cost for a sample of nine cars, in hundreds of dollars, is provided below 10 6 8 10 4 3.5 7.5 8 9 What is the mean of the total damage suffered for this sample of cars?

$733

Interest rates for home mortgages have, in general, declined during recent months. With the apparent favorable influence for new-home building, there seems to be a clear relationship between x = the prevailing mortgage interest rates and y = the number of new houses being built per month in a Midwestern city over a period of 18 months. A scatterplot of the data collected shows that the linear model is appropriate. The equation of the least-squares regression line isNumber of new houses = 672.89 - 30.65 × Interest rate and r 2 = 0.49.What is the correlation coefficient between Interest rate and Number of new houses being built?

-0.7

Colorectal cancer (CRC) is the third most commonly diagnosed cancer among Americans (with nearly 147,000 new cases), and the third leading cause of cancer death (with over 50,000 deaths annually). Research was done to determine whether there is a link between obesity and CRC mortality rates among African Americans in the United States by county. Below are the results of a least-squares regression analysis from the software StatCrunch. What fraction of the variation in mortality rates is explained by the least-squares regression? -0.0067 1 13.45 0

0

Consider the following data which describe the amount of time in minutes students spend studying for a quiz:10, 11, 11, 12, 12, 14, 15, 18, 19, 20, 22, 24, 39, 40, 41, 44, 46, 50, 52, 52, 53, 55, 70.What numbers make up the leaf of the first stem if you were splitting the stems?

0,1,1,2,2,4

Students at a small, private university are required to take a basic statistics course. The table below summarizes one of the classes by gender and year in school. Year in school Gender Freshman Sophomore Junior Senior TOTAL Male 15 3 2 0 20 Female 50 20 8 2 80 TOTAL 65 23 10 2 100 What proportion of the students in the class are seniors?(Do Not Round)

0.02

The 94 students in a statistics class are categorized by gender and by the year in school. The numbers obtained are displayed below: Year in school GenderFreshmanSophmoreJuniorSeniorGraduateTotal Male 1 2 9 17 2 31 Female 23 17 13 7 3 63 Total 24 19 22 24 5 94 The data are going to be summarized by computing the conditional distributions of year in school for male and female students. What would be the entry for male sophomores?

0.065

The British government conducts regular surveys of household spending. The average weekly household spending on tobacco products and spending on alcoholic beverages for each of 11 regions in Great Britain were recorded. A scatterplot of spending on tobacco versus spending on alcohol is given below: What is the most plausible value for the correlation between spending on tobacco and spending on alcohol?

0.08

Simple random samples of 100 high school students are sampled from each grade level, for a total of 400 high school students. They are asked to rate the performance of the President of the United States on a scale from 1 to 5 (1 = poor; 5 = excellent). The results are presented below: Performance rating Class 1 2 3 4 5 TOTAL Freshman 20 26 36 11 7 100 Sophomore 17 23 29 28 3 100 Junior 11 34 22 23 10 100 Senior 22 24 17 25 12 100 TOTAL 70 107 104 87 32 400 What proportion of the seniors in the sample assigned the President an "excellent" rating?(Do Not Round)

0.12

Prior to graduation, a high school class was surveyed about their plans after high school. The table below displays the results by gender: Plans Gender 4-year college 2-year college Military Work Other Male 198 36 4 14 16 Female 176 36 1 3 5 If the data are going to be summarized by computing the conditional distributions of plans after high school for male and female high school students, what would be the entry for "male" and "2-year college"?

0.134

A survey was conducted involving 303 subjects concerning their preferences with respect to the size of car they would consider purchasing. The following table shows the count of the responses by gender of the respondents: Size of Car Gender Small Medium Large Total Female 58 63 17 138 Male 79 61 25 165 Total 137 124 42 303 In the conditional distribution for preference of car size among male respondents, the entry for large cars is _______.

0.152

Chocolate bars produced by a certain machine are labeled with 8.0 ounces. The distribution of the actual weights of these chocolate bars is Normal with a mean of 8.1 ounces and a standard deviation of 0.1 ounces. A chocolate bar is considered underweight if it weighs less than 8.0 ounces. What proportion of chocolate bars weighs less than 8.0 ounces?

0.159

A survey was conducted involving 303 subjects concerning their preferences with respect to the size of car they would consider purchasing. The following table shows the count of the responses by gender of the respondents: Size of Car Gender Small Medium Large Total Female 58 63 17 138 Male 79 61 25 165 Total 137 124 42 303 Among all respondents, the proportion of female respondents who preferred small cars is __________.

0.191

Students at a small, private university are required to take a basic statistics course. The table below summarizes one of the classes by gender and year in school. Year in school Gender Freshman Sophomore Junior Senior TOTAL Male 15 3 2 0 20 Female 50 20 8 2 80 TOTAL 65 23 10 2 100 What proportion of students is male?(Do Not Round)

0.2

The 94 students in a statistics class are categorized by gender and by the year in school. The numbers obtained are displayed below: Year in school GenderFreshmanSophmoreJuniorSeniorGraduateTotal Male 1 2 9 17 2 31 Female 23 17 13 7 3 63 Total 24 19 22 24 5 94 What proportion of the statistics students in this class are male?

0.33

A market research company employs a large number of typists to enter data into a computer database. The time it takes for potential new typists to learn the computer system is known to have a Normal distribution with a mean of 90 minutes and a standard deviation of 18 minutes. A candidate is automatically hired if she learns the computer system in less than 100 minutes. A cut-off time is set at the slowest 10% of the learning distribution. Anyone slower than this cut-off time is definitely not hired.What proportion of candidates will be hired automatically?

0.711

Prior to graduation, a high school class was surveyed about their plans after high school. The table below displays the results by gender: Plans Gender 4-year college 2-year college Military Work Other Male 198 36 4 14 16 Female 176 36 1 3 5 If the data are going to be summarized by computing the marginal distribution of plans after high school, what would be the entry for "4-year college"?

0.765

The following boxplot is of the birth weights (in ounces) of 160 infants born in a local hospital. The median birth weight is approximately ________________. 110 ounces 100 ounces 90 ounces 120 ounces

110 ounces

A study was conducted on the distance that various brand name golf balls would travel. The study involved the use of a standard testing machine using a seven iron. A selection of results from the study is given below for the distance (in yards) for each brand of ball. 144.0 145.8 138.7 141.3 142.8 143.8 145.8 144.5 The mean and the standard deviation s of these measurements (in yards) are, respectively,

143.34 and 2.39.

The asking prices (in thousands of dollars) for a sample of 13 houses currently on the market in Neighborville are listed below. For convenience, the data have been ordered. 175 199 205 234 259 275 299 304 317 345 355 384 549 What is the five-number summary?

175 219.5 299 350 384 175 234 299 331 549 199 219.5 299 350 549 Correct! None of the above

The Environmental Protection Agency records data on the fuel economy of many different makes of cars. Data on the mileage of 20 randomly selected cars are listed below. The values are ordered for convenience. ​ 12 13 15 16 16 17 18 18 19 19 20 20 22 23 24 26 26 27 27 29 ​ What is the median mileage for these 20 cars?

19.5

The weights of packets of cookies produced by a certain manufacturer have a Normal distribution with a mean of 202 grams and a standard deviation of 3 grams. What is the weight that should be stamped on the packet so that only 1% of the packets are underweight?

195 grams

A study was conducted on the distance that various brand name golf balls would travel. The study involved the use of a standard testing machine using a seven iron. It was determined that the mean distance was = 237.8 yards with a standard deviation of s = 4.58 yards. It was later determined that the measuring instrument had been calibrated incorrectly and hence gave measurements that were consistently too large by 2.5 yards. Since the results of the study were to be published in Europe, it was desired to convert all measurements from yards into meters. A statistician determined that the appropriate transformation to correct the error and convert to meters in this case would be ​ ​ y = 0.9144x - 2.286 ​ where x is the measurement in yards and y in meters. The mean and standard deviation (in meters), respectively, should now be reported as _____.

215.2 and 4.19

A sample of 16 people is taken, and their weights are measured. The standard deviation of these 16 measurements is computed to be 5.4.What is the variance of these measurements?

29.16 pounds^2

A softdrink machine can be regulated so that it discharges an average of ounces per cup. If the ounces of fill are Normally distributed with a standard deviation of 0.4 ounces, what value should be set at so that 6-ounce cups will overflow only 2% of the time?

5.18

Answer true or false to the following statements. A) The correlation, r, is always positive. B) The correlation, r, is always negative. C) The correlation, r, is a number between -100 and 100. D) The correlation, r, measures the shape of a scatterplot.

A) False, B) False, C) False, D) False

A simple random sample of eight drivers was selected. All eight drivers are insured with the same insurance company, and all have similar auto insurance policies. The following table lists their driving experiences (in years) and monthly auto insurance premiums: Driving experience (years) 5 2 12 9 15 6 25 16 Monthly auto insurance premium ($) 64 77 50 71 44 56 42 60 Predict the monthly auto insurance premium for a driver with 10 years of driving experience.(Round to 2 decimal places)

59.63

Chocolate bars produced by a certain machine are labeled with 8.0 ounces. The distribution of the actual weights of these chocolate bars is Normal with a mean of 8.1 ounces and a standard deviation of 0.1 ounces. A chocolate bar is considered underweight if it weighs less than 8.0 ounces. How should the chocolate bar wrappers be labeled so that only 1% of such bars are underweight?

7.87 ounces

Determine whether each of the following statements regarding residuals is true or false. A) The sum of the residuals is always 0 B) A plot of the residuals is useful for assessing the fit of the least-squares regression line. C) The value of a residual is the observed value of the response minus the value of the response that one would predict from the least-squares regression line.

A) True, B) True, C) True

The Environmental Protection Agency records data on the fuel economy of many different makes of cars. Data on the mileage of 20 randomly selected cars are listed below. The values are ordered for convenience. ​ 12 13 15 16 16 17 18 18 19 19 20 20 22 23 24 26 26 27 27 29 ​ What is the interquartile range for the mileage data?

8.5 miles per gallon

The histogram below represents the height (in inches) of the gold medal-winning high jumps for the Olympic Games up to Sydney 2000. What is approximately the mean height?

82 inches

A well-known maker of jams and jellies packages its jams in jars labeled "250 milliliters." The process used to fill the jars is known to dispense an amount of jam that is a Normally distributed variable with = 252 milliliters and = 0.9 milliliters. If changing while keeping the same were possible for this process, what should be set at so that the percentage of jars filled with less than 250 milliliters will be at most 0.2%?

= 0.69

Which of the following statements are FALSE? Bar graphs, unlike histograms, can have blank spaces between the bars to separate the items being compared. The distribution of a categorical variable lists the categories and gives the counts or the percentages of individuals in each category. A histogram shows the distribution of counts or percentages among the values of a single quantitative variable. A stemplot is particularly valuable for displaying the shape of the distribution of a categorical variable when there are few observations. A bar chart is a useful graphical tool for describing the shape of the distribution of a categorical variable.

A stemplot is particularly valuable for displaying the shape of the distribution of a categorical variable when there are few observations.

The Insurance Institute for Highway Safety publishes data on the total damage suffered by compact automobiles in a series of controlled, low-speed collisions. The cost for a sample of nine cars, in hundreds of dollars, is provided below10 6 8 10 4 3.5 7.5 8 9What is the interquartile range of the above data?

A value between $200 and $460

What method is useful when comparing two distributions using a stemplot?

Back-to-back stemplots

Is age a good predictor of salary for CEOs? Sixty CEOs between the age of 32 and 74 were asked their salary (in thousands). The results of a statistical analysis are shown below: What are possible reasons for a correlation around .13 for this problem?

Age is not a good predictor and something else may be a better a predictor

Which of the following variables is quantitative? The number of tenured professors at a large university The number of hurricanes each year for the years 2000 to 2010 The amount of time a student spends on the Internet in a week None of the above All of the above

All of the above

Which of the following statements about least-squares regression involving two quantitative variables, x and y, is/are TRUE? The square of the correlation, , is the fraction of the variation in the values of y that is explained by the least-squares regression of y on x. The least-squares regression line always passes through the point ( , ). The least-squares regression line of y on x is the line that makes the sum of the squares of the vertical distances of the data points from the line as small as possible. Correct! All of the above are true. A change of one standard deviation in x corresponds to a change of r standard deviations in y.

All of the above are true.

When examining a distribution of a quantitative variable, which of the following features do we look for? Deviations from overall patterns such as outliers The number of peaks or modes All of the these Overall shape, center, and spread Symmetry or skewness

All of the these

The appearance of a histogram will change when you _______. change the class size add more data remove outliers All of these

All of these

When examining a scatterplot for direction, you are looking to see if __________. high values of the two variables in the scatterplot tend to occur together high values of one variable tend to occur with low values of the other variable there is a positive association there is a negative association Correct! All of these

All of these

Is age a good predictor of salary for CEOs? Sixty CEOs between the age of 32 and 74 were asked their salary (in thousands). The results of a statistical analysis are shown below: What percent of the variation in CEO salaries is explained by age alone?

Around 1.6%

Which of the following statements about Normal quantile plots is/are FALSE? In constructing a Normal quantile plot, each data point is plotted against its corresponding Normal score. On a quantile plot, outliers will appear as points that are far away from the overall pattern of the plot. The Normal quantile plot is a very useful graphical tool for assessing the adequacy of the Normal model. Because you will see the usual mound-like appearance of the Normal distribution on a histogram, it is more helpful than the quantile plot for assessing Normality. If the points on a Normal quantile plot lie close to a straight line, the plot indicates that the Normal model is an adequate representation for the data.

Because you will see the usual mound-like appearance of the Normal distribution on a histogram, it is more helpful than the quantile plot for assessing Normality.

We have a data set where the cases are college students. One of the variables in the data set is "hometown." What type of variable is hometown?

Categorical

A researcher measured the height (in feet) and volume of usable lumber (in cubic feet) of 32 cherry trees. The goal is to determine if the volume of usable lumber can be estimated from the height of a tree. The results are plotted below: Select all descriptions that apply to the scatterplot. A) There is a positive association between height and volume. B) There is a negative association between height and volume. C) There is an outlier in the plot. D) The plot is skewed to the left. E) Both A and C

E) Both A and C

Malaria is a leading cause of infectious disease and death worldwide. The table below represents the mean number of reported malaria cases (between 1996 and 2006) for each of 10 West African countries, as published in the journal Statistica Neerlandica in 2010. The variable "country" is a quantitative variable.

False

True or False. Influential outliers are easy to detect because the residuals will always be very large compared to the residuals of the other observations.False

False

True or False. The correlation, r, is negative if the relationship between two quantitative variables is weak.

False

A consumer agency is testing appliances for a series of articles in their magazine. Currently they are working with cooktops and ranges. They have selected 16 of the most commonly used models. Using a series of tests, the agency will estimate the lifetime of these models. A histogram of these (estimated) lifetimes is shown below. What is the proportion of these appliances that is estimated to last longer than 15 years?

It cannot be determined from this graph.

A scatterplot of a variable y versus a variable x produced the scatterplot shown below. The value of y for all values of x is exactly 1.0.What do we know about the correlation between x and y?

It is 0 because y does not change as x increases

In the blood pressure study by the WHO, the mean systolic blood pressure in the United States was reported to be 120 mmHg. The 75th percentile of the distribution of SBP measurements was found to be 109.2 mmHg. From this, it can be determined that the SBP standard deviation is

It is not within ± 0.5 of any of the above.

The scatterplot below represents a small data set. The data were classified as either type 1 or type 2. Those of type 1 are indicated by x's and those of type 2 by o's.What do we know about the overall correlation of the data in this scatterplot?

It is positive.

The Environmental Protection Agency records data on the fuel economy of many different makes of cars. Data on the mileage of 20 randomly selected cars are listed below. The values are ordered for convenience. ​ 12 13 15 16 16 17 18 18 19 19 20 20 22 23 24 26 26 27 27 29 ​ If the value 29 were misrecorded and should really be 21, what would the median mileage be for these 20 cars?

It would stay the same.

Do heavier cars use more gasoline? To answer this question, a researcher randomly selected 15 cars. He collected data about the weight (in hundreds of pounds) and the mileage (mpg) for each car. From a scatterplot made with the data, a linear model seems appropriate.Fill in the blank. The variable _______ is the response variable in this study.

Mileage

Is age a good predictor of salary for CEOs? Sixty CEOs between the age of 32 and 74 were asked their salary (in thousands). The results of a statistical analysis are shown below: Is age a good predictor of salary?

No, the correlation and r2 is low.

The number of Facebook friends students at a university have are Normally distributed with a mean of 1200 and a standard deviation of 200. What percentage of students has exactly 1000 Facebook friends? 15.86% 84.13% 42.07% None of the above

None of the above

Volunteers for a research study were divided into three groups. Group 1 listened to Western religious music, Group 2 listened to Western rock music, and Group 3 listened to Chinese religious music. The blood pressure of each volunteer was measured before and after listening to the music, and the change in blood pressure (blood pressure before listening minus blood pressure after listening) was recorded.A scatterplot of change in blood pressure (mmHg) versus the type of music listened to is given below: What do we know about the correlation between change in blood pressure and type of music? It is positive. It is first negative then positive. It is negative. None of these

None of these

Which one of the following statements is TRUE? When calculating the correlation, r, it is important to make sure y is the explanatory variable and the x is the response variable. When calculating the correlation, r, it is important to make sure x is the explanatory variable and the y is the response variable.

None of these

At a Canadian agricultural fair held in Neguac, New Brunswick, giant pumpkins were entered into a competition. The following stem-and-leaf plot of the weight (in pounds) of the 35 pumpkins in the competition was constructed, where, for example, 9|4 represents 940 pounds. The quartiles, Q1 and Q3, for these data are Q1 = 322 and Q3 = 716. Q1 = 320 and Q3 = 640. Q1 = 490 and Q3 = 660. Correct! Q1 = 320 and Q3 = 660. Q1 = 90 and Q3 = 1190

Q1 = 320 and Q3 = 660

Suppose you are interested in comparing the quality of different hospitals based on infections occurred from surgery. What would be the best way to measure such a variable?

Rate of infection

Which of the following variables is categorical? The number of Facebook friends you have The available food choices in the student cafeteria The amount of time a student spends on the Internet in one day None of the above

The available food choices in the student cafeteria

The first day of class the professor collects information on each student to make a data set that will be analyzed throughout the semester. The information asked includes hometown, GPA, number of classes, number of siblings, and favorite subject. What are the cases in this data set? None of the above The semester The professor The college students

The college students

Consider the following scatterplot of two variables x and y:What can we conclude from this graph?

The correlation between x and y is close to 0.

Which one of the following statements is TRUE? The correlation, r, measures the strength of the linear relationship between two categorical variables. The correlation, r, measures the strength between one quantitative variable and one categorical variable. The correlation, r, measures the strength of the linear relationship between two quantitative variables.

The correlation, r, measures the strength of the linear relationship between two quantitative variables.

A researcher computed the average Math SAT score of all high school seniors who took the SAT exam for each of the 50 states. The researcher also computed the average salary of high school teachers in each of these states and plotted these average salaries against the average Math SAT scores for each state. The plot showed a distinct negative association between average Math SAT scores and average teacher salaries. The researcher can legitimately conclude which of the following?

The data used by the researcher do not provide evidence that increasing the salary of teachers will cause the performance of students on the Math SAT to get worse.

Is age a good predictor of salary for CEOs? Sixty CEOs between the age of 32 and 74 were asked their salary (in thousands). The results of a statistical analysis are shown below: How do you interpret the intercept for this problem? A CEO at birth is expected to make around $242,000. None of the above A CEO at 100 years old is expected to make around $555.00 The intercept is not useful for this problem.

The intercept is not useful for this problem.

The World Malaria Report (2008) has information on the number of reported malaria cases from 2005 and 2006 for the 10 countries listed in West Africa. The data are presented in the table below. If the number of malaria cases for Ghana were removed from this data set, what would happen to the mean of the entire data set for the year 2005?

The mean would change.

Do heavier cars use more gasoline? To answer this question, a researcher randomly selected 15 cars. He collected data about the weight (in hundreds of pounds) and the mileage (mpg) for each car. From a scatterplot made with the data, a linear model seems appropriate.The equation of the least-squares regression line is = 40.4 - 0.521xWhich of the following descriptions of the value of the slope is the correct description?

The mileage is expected to decrease by 0.521 when the weight of a car increases by 100 pounds.

A researcher reports that, on average, the participants in his study lost 10.4 pounds after 2 months on his new diet. A friend of yours comments that she tried the diet for 2 months and lost no weight, so clearly the report must be a fraud. Which of the following statements is correct? In order for the study to be correct, we must now add your friend's results to those of the study and recalculate the new average. Your friend must not have followed the diet correctly because she did not lose weight. Because your friend did not lose weight, the report must not be correct. Correct! The report gives only the average. This does not imply that all participants in the study lost 10.4 pounds or even that all participants lost weight. Your friend's experience does not necessarily contradict the study results.

The report gives only the average. This does not imply that all participants in the study lost 10.4 pounds or even that all participants lost weight. Your friend's experience does not necessarily contradict the study results.

Two variables are ______ if knowing the values of one of the variables gives one information about the other variable.

associated

We are interested in determining if students who graduate from larger universities receive greater starting salaries than students who graduate from smaller universities. We collected data from 50 small universities and 50 large universities to examine this relationship. This is an example of ________

benchmarking

The tails of a distribution show the ______

extreme values

You can describe the overall pattern of a scatterplot by the _____.

form, direction, and strength

The World Malaria Report (2008) has information on the number of reported malaria cases from 2005 and 2006 for the 10 countries listed in West Africa. The data are presented in the table below. The median of the reported malaria cases in 2005 is _________.

less than 1,000,000

The World Malaria Report (2008) has information on the number of reported malaria cases from 2005 and 2006 for the 10 countries listed in West Africa. The data are presented in the table below. The mean reported malaria cases in 2006 is _________.

less than 2,000,000

Categorical variables place cases into ____ group(s).

many