Exam 5: Statistical Reasoning

State whether the scatter diagram shows strong positive correlation, weak positive correlation, strong negativecorrelation, weak negative correlation, or no correlation. -

Provide an appropriate response. -Construct a frequency table and the corresponding histogram in which the following conditions are satisfied: - The frequency for the second class is twice the frequency of the first class - In the histogram, the area of the bar corresponding to the second class is four times the area of the bar corresponding to the first class

Use the graph to answer the question. - Mike decides to buy shares of companies A, B, and C, which were initially selling for the same price. The changes in each stock's value are shown in the graph above. Could Mike ever have made a profit off stock A if he had sold at the right time? If so, when should he have sold to make the maximum profit? Answer the same questions for stocks B and C.

Describe how you would apply the five basic steps of a statistical study to the given issue. -As an executive of a large software company, you want to know whether there has been an increase in levels of stress amongst your employees.

Answer as requested. -Which of the following is likely a cause-and-effect relationship?

Answer the question. -Which of the following describes a study in which the patients do not know whether they are receiving the treatment or the placebo but the experimenters do know?

The stack plot below shows the value of each of Danny's investments. The stack plot contains three regions. Theuppermost unshaded region represents the value of Danny's investment in individual stocks. The center shaded regionrepresents the value of Danny's investment in mutual funds and the bottom region in black represents the value ofDanny's investment in a CD. The thickness of a region at a particular time tells you its value at that time. Use the graph to answer the question. -In year 8, approximately what percentage of Danny's total investment was in mutual funds?

Construct a line chart for the data. - Student Test Scores Score Frequency 10-14 2 15-19 5 20-24 13 25-29 17 30-34 6

Answer the question. -The graph below shows estimated world population for the period 4000 BC $4000 \mathrm { BC } - 2000 \mathrm { AD }$ Note that the logarithm of the world population and not actual population is plotted on the vertical axis. This means, for example, that when the graph reaches 7 on the vertical scale, world population is $10 ^ { 7 }$ and when the graph reaches 9 on the vertical scale, world population is $10 ^ { 9 }$ . Why must the graph be interpreted with care? If the graph is not interpreted with care what misleading impression might one have of world population during the period 4000 BC - 2000 AD? Why do you think that the graph was presented in this form?

The stack plot below shows the value of each of Danny's investments. The stack plot contains three regions. Theuppermost unshaded region represents the value of Danny's investment in individual stocks. The center shaded regionrepresents the value of Danny's investment in mutual funds and the bottom region in black represents the value ofDanny's investment in a CD. The thickness of a region at a particular time tells you its value at that time. Use the graph to answer the question. -In which year was the total value of Danny's investments the greatest?

Create a graphical display for the data given. You may choose any graphic type that you feel is appropriate. Write a fewsentences explaining why you chose this type of display and a few sentences describing any interesting patterns in thedata. -The table below gives information about U.S. families with children under the age of 18. The table shows the percentage of these families that are two-parent families, the percentage that are maintained by a single mother, and the percentage that are maintained by a single father. U.S. Families with Children Under 18 Year Two-parent Single mother Single father 1981 77.6\% 20.0\% 2.4\% 1984 74.2\% 22.9\% 2.8\% 1987 73.0\% 23.7\% 3.2\% 1990 71.9\% 24.2\% 3.9\% 1993 69.8\% 25.9\% 4.3\% 1996 68.4\% 26.6\% 5.0\% 1999 68.2\% 26.3\% 5.5\% 2002 68.3\% 25.9\% 5.8\%

Choose the best wording for the question in the study. -A researcher wishes to determine the level of support for a new environmental law. Which of the following questions will produce the most accurate results?

Use the indicated bin size to construct a frequency table for the set of data. Include columns for relative frequency andcumulative frequency. -The weekly incomes (in dollars)of 20 college students are shown below. 120 180 240 330 165 178 215 268 0 305 90 144 336 116 0 74 136 85 165 62 Use 50 -point bins (0-49,50-99 , etc )

State whether the scatter diagram shows strong positive correlation, weak positive correlation, strong negativecorrelation, weak negative correlation, or no correlation. -

The stack plot below shows the value of each of Danny's investments. The stack plot contains three regions. Theuppermost unshaded region represents the value of Danny's investment in individual stocks. The center shaded regionrepresents the value of Danny's investment in mutual funds and the bottom region in black represents the value ofDanny's investment in a CD. The thickness of a region at a particular time tells you its value at that time. Use the graph to answer the question. -In year 0, approximately what percentage of Danny's total investment was in the CD?

State whether you think that the variables have strong positive correlation, weak positive correlation, strong negativecorrelation, weak negative correlation, or no correlation. -The unemployment rate and the number of homeless people.

Answer the question. -What name is given to a statistical graph where a quantity is represented by a curve and has the same value everywhere along the curve?

The stack plot below shows the value of each of Danny's investments. The stack plot contains three regions. Theuppermost unshaded region represents the value of Danny's investment in individual stocks. The center shaded regionrepresents the value of Danny's investment in mutual funds and the bottom region in black represents the value ofDanny's investment in a CD. The thickness of a region at a particular time tells you its value at that time. Use the graph to answer the question. -In year 8, what was the approximate value of Danny's investment in mutual funds?

Use the guidelines to evaluate the study. Discuss flaws that you see in the study. -A documentary which appeared on a TV station owned by a large biotech company announced that 77% of Americans are in favor of genetically modified foods. The researcher for the documentary had conducted a telephone poll of 200 people selected randomly from the phone book. Each person in the sample had been asked "Are you in favor of increasing the production of genetically modified foods in order to increase the world food supply?"

Use the graph to answer the question. -This double-bar graph shows the number of male (M)and female (F)athletes at a university over a four-year period. Compare the trend in the number of male athletes during the four-year period and the trend in the Number of female athletes during the four-year period .