1. A group of students played a game in which they earned points for answering questions correctly. The following dotplot shows the total number of points earned by each student.
Which of the following is the best description of the distribution of points earned?
(A) Approximately normal
(B) Bimodal without a gap
(C) Bimodal with a gap
(D) Skewed to the right without a gap
(E) Skewed to the right with a gap
2. The table shows the responses from 103 people when asked if they support a proposal to expand the public library.
One person from those who responded will be selected at random. Which of the following is closest to the probability that the person selected will be someone who responded no, given that the person selected is age 55 or older?
3. Data were collected on the fiber diameter and the fleece weight of wool taken from a sample of 20 sheep. The data are shown in the following graphs. Graph 1 is a scatterplot of fleece weight versus fiber diameter with the respective least-squares regression line shown. Graph 2 is the associated plot of the residuals versus the predicted values.
One point is circled on graph 1. Five points labeled A, B, C, D, and E are identified on graph 2. Which point on graph 2 represents the residual for the circled point on graph 1 ?
1. Thirty-four college students were asked how much money they spent on textbooks for the current semester.Their responses are shown in the following stemplot.
(a) Describe a procedure for identifying potential outliers, and use the procedure to decide whether there are outliers among the responses for the money spent on textbooks.
(b) Based on the stemplot, write a few sentences describing the distribution of money spent on textbooks for the 34 students.
2. A real estate agent working in a large city believes that, for three-bedroom houses, the selling price of the house decreases by approximately $2,000 for every mile increase in the distance of the house from the city center. To investigate the belief, the agent obtained a random sample of 20 three-bedroom houses that sold in the last year. The selling price, in thousands of dollars, and the distance from the city center, in miles, for each of the 20 houses are shown in the scatterplot. The table shows computer output from a regression analysis of the data.
(a) Assume all conditions for inference are met. Construct and interpret a 95 percent confidence interval for the slope of the least-squares regression line.
(b) Does the confidence interval contradict the agent’s belief about the relationship between selling price and distance from the city center? Justify your answer.