Stats Test 6-9

A researcher collected data on the Asian years and the growth of sea turtles. The following graph is a residual plot of the regression of growth versus age. Does the residual plot support the appropriateness of a linear model?

No, because the graph displays a U-shaped pattern

A scatterplot of students heights, in inches, versus corresponding arm span length, in inches, is shown below. One of the points in the graph is labeled a period of .8 is removed which of the following statements would be true?

The slope of the least squares regression line increases and the correlation coefficient increases

A tennis ball was thrown in the air. The height of the ball from the ground was recorded every millisecond from the time the ball was thrown until it reached the height from which it was thrown. The correlation between the time and a height was computed to be zero. What does this correlation should just about the relationship between time and height?

There is no linear relationship between time and height

which of the following is the best description of a positive association between two variables?

As the value of one of the variables increases, the value of the other variable tends to increase

For random sample of 20 professional athletes, there is a strong, linear relationship between the number of hours of exercise per week and the resting heart rate. For the athletes in the sample, those who exercise more hours per week tend to have lower resting heart rate than those who exercise less. Which of the following is a reasonable value for the correlation between the number of hours athletes exercise per week and they're resting heart rate?

-0.87

an exponential relationship exists between the explanatory variable and the responsible variable and a set of data. The common logarithm of each value of the response of variable is taken, and the least square regression line has an equation of log (Y) equals 7.3-1.5 X. Which of the following is closest to the predictive value of the response variables for X equals 4.8?

1.26

which of the following statements about a lease squares regression analysis is true? 1) appoint with a large residual is an outlier. 2) appoint with a hide leverage has Y value that is not consistent with the other Y values in the stat 3) The removal of an influential point from a data set could change the value of the correlation coefficient

3 only

dairy farmers are aware there is often a linear relationship between the age, in years, of a dairy cow in the amount of milk produced, and gallons per week. The least squares regression line produced from a random milk sample is milk equals 40.8-1.1 (age). Based on the model, what is the difference in predicted amounts of milk produced between a cow of five years in a cow of 10 years?

A cow or five years is predicted to produce 5.5 more gallons per week

at a large airport, data were recorded for one month on how many baggage items were unloaded from each flight upon arrival as well as the time required to deliver all the baggage items on the flight to the baggage claim area. A scatterplot of the two variables indicated a strong positive linear association between the variables. Which of the following statements is a correct interpretation of the word strong in the description of the association?

The actual time required to deliver all the items to the baggage claim area based on the number of items unloaded will be very close to the predicted time by the least squares model

A road runner is a desert bird that tends to run instead of fly. While running, the Road Runner uses its tail to balance. A sample of 10 road runners was taken and the birds total length and centimeters and tail length and centimeters were recorded. The output shown in the table is from Elise squares regression to predict the tail length and given the total length. Suppose A road runner has a total tail length of 59.0 cm and a tail length of 31.1 cm. Based on the residual, does the regression model over estimate or underestimate The tail length of the Road Runner?

Under estimate, because the residual is positive

A field researcher who studies lions conjectured that the more time a Cubs spins playing, the sooner the couple begin to hunt. Observational data were collected from 20 lion cubs. The researcher recorded how long they spent playing in the age when they began hunting. Because male and female lions have different hunting behaviors, the research a record of the data for males and found female separately. The two scatterplot show the data for the 10 female lions and 10 male lions. Based on the scatterplots, for which gender does there appear to be evidence that the more time a lion cub spends playing, the sooner the lion cub is likely to begin hunting?

for females only

for a specific species of fish in a pond, a wildlife biologist wants to build a regression equation to predict the weight of a fish based on its length. The biologist collects a random sample of the species of fish and finds that the length varies from 0.75 to 1.35 inches. The biologist uses this data from the sample to create a single linear regression model. Would it would be appropriate to use this model to predict the weight of a fish other species that is 3 inches long?

no, because 3 inches falls above the maximum value of lengths in the sample