you measure the age, martial status and earned income of an SRS of 1463 women. the number and type of variables you have measured is
three; one categorical and two quantitative
X and Y are two categorical variables. the best way to determine if there is a relation between them is to
make a two-way table of the X and Y values.
which of the following statements is not true
the median is always greater than the mean
a set of data has a mean that is much larger than the median. which of the following statements is most consistent with this information
the distribution is skewed right
the bar graph below summarizes responses of dog owners to the question "where in the car do you let your dog ride?
these data could also be presented in a pie chart
there are three children in a room, ages three, four, and five. if a four-year-old child enters the room the
mean age will stay the same but the variance will decrease
Different writers have different styles. one way to quantify this difference is to compare this distribution of word lengths in their work. below are parallel boxplots describing the distributions of word lengths for the first 60 words in....
The median word length for rowling is longer than for either starnes or James
Use scenario 1-4. the interquartile range for the number of AP courses is
2
Use scenario 1-4. Which of the following is the correct boxplot
B (skewed left and no median line)
A sample of production records for an automobile manufacturer shows the following figures for production per shift.... the variance of the sample is
50.00.
A lobster fisherman is keeping track of the productivity of a set of traps he has placed in a favorite location. Below are the numbers of lobsters in these traps over the course of 12 different hauls. According to the 1.5x IQR rule, which values in the ab
14 only
Scenario 4-6
Does caffeine improve exam performance? Suppose all students in the 8:30 section of a course are given a "treatment" (two cups of coffee) and all students in the 9:30 section are not permitted to have any caffeine before a mid term exam.Use S
confounding
Scenario 4-1
A sports writer wants to know how strongly Lafayette residents support the local minor league baseball team, the Lafayette Leopards. She standed outside the stadium before a game and interviewed the first 20 people who enter the stadium. Use
all residents of Lafayette
The stemplot below shows the number of home runs hit in 2008 by members of the Philadelphia Phillies, who won major League Baseball's World Series that year. (Each of the 13 players who appeared in at least half the Phillies' games that year is included).
0, 6.5, 11, 28.5, 48
You plan to give a math achievement test to samples of 15 year-olds from both the U.S and Korea in order to compare mathematics knowledge in the two countries. In each country, you will randomly choose:
300 students from low-income families
400 students f
stratified random sample
Scenario 3-1
The height (in feet) and volume (in cubic feet) of usable lumber of 32 cherry trees are measured by a researcher. The goal is to determine if volume of usable lumber can be estimated from the height of a tree. Use Scenario 3-1. In this study,
volume of lumber
Use Scenario 3-1. If the data point (65,70) were removed from this study, how would the value of the correlation r change?
r would be larger, since this point does in the pattern of the rest of the data
Scenario 3-2
The following table and scatter plot present data on wine consumption (in liters per person per year) and death rates from heart attacks (in deaths per 100,000 people per year) in 19 developed Western countries. Use Scenario 3-2. The scatterp
countries that drink more wine have lower death rates from heart disease
Consider the following scatter plot of two variables, X and Y. We may conclude that the correlation between X and Y
is close to 1, even though the relationship is not linear
The correlation between the age and the height of children is found to be about r=0.7. Suppose we use the age x of a child to predict the height y of the child. We conclude that
the fraction of the variation in heights explained by the least-squares regression line of y on x is 0.49.
Which of the following statements concerning residuals is true?
All of the above
A stemplot of a set of a data is roughly symmetric, but the data do not even approximately follow the 68-95-99.7 rule. We conclude that the data are
not normal
Scenario 3-8
A fisheries biologist studying whitefish in a Canadian Lake collected data on the length (in centimeters) and egg production for 25 female fish. A scatter plot of her results and computer regression analysis of egg production versus fish leng
Eggs= -142.74+39.25 (Length)
The owner of a chain of supermarkets notices that there is a positive correlation between the sales of beer and the sales of ice cream over the course of the previous year. During seasons when sales of beer were above average, sales of ice cream also tend
It is likely that sales of both beer and ice cream are confounded with a lurking variable, such as seasonal variation in temperature.
A double-blind experiment was conducted to evaluate the effectiveness of the Salk polio vaccine. The purpose of keeping the diagnosing physicians ignorant of the treatment status of the experimental subjects was to
eliminate a possible source of bias
Scenario 12-10
Use of the internet worldwide increased steadily from 1990-2002. A residual plot for the regression of worldwide Internet Users (in millions) on Year is shown below. Use Scenario 12-10. Suppose we use the regression whose residuals are show
The prediction would probably underestimate the true number of Internet users in 1991
Use Scenario 12-10. A scatterplot of Internet Users (in millions) versus Year is strongly linear, suggesting that linear regression of this transformation may be more appropriate. Below is a computer regression analysis of the transformed data (note that
4.92