Name: Langholz Fall 2012Midterm 1 Review1. The Johnsons have 5 children. Their ages are: 3, 6, 7, 11, 18.What is the mean age? What is the standard deviation of the ages?2. A class has 10 students. The scores on the latest test, in order were:88 79 81 81 101 82 83 84 90 79What is the median score? What is Q3? What is the IQR?3. Consider the following two-way table of 49 men and women cell phone types.Male FemaleIphone 13 10Other Phone 10 16What percent of all the people surveyed are men and have iPhones?What percent of women have iPhones?What percent of iPhone users are women?Is there evidence that gender is associated with iPhone usage?Name: Langholz Fall 20124. Researchers conducted a study to see if there is a relationship between drinking wine and a lower riskof heart disease. They find people willing to participate in the study and monitor the people’s drinkinghabits and their heart health. The researchers find that people who regularly drink wine generally havebetter heart health.Was this an experiment or an observational study?Does this mean that drinking wine is good for your health?5. Consider the following boxplot:What is the median? What is Q1? What is the IQR?6. Michael played on his high school’s soccer team and basketball team last year. He scored 18 goalsthroughout the soccer season and made 28 baskets throughout the basketball season. The followingsummarize the total number of goals and baskets by each of his team members throughout the season.Mean Standard DeviationSoccer Goals 10 4Basketball Baskets 25 5What is Michael’s z-score in soccer?Based on these statistics alone, is Michael a better soccer player or basketball player?Name: Langholz Fall 20127. A tire manufacturer believes that the treadlife of its snow tires can be described as unimodal, symmetric,and mound-shaped with a mean of 30,000 miles and standard deviation of 3,000 miles. What do we knowabout the IQR of this distribution?(a) The IQR is between 3,000 and 6,000 miles.(b) The IQR is larger than 6,000 miles.(c) It does not make sense to calculate the IQR because the distribution is unimodal and symmetric(d) The IQR is between 27,000 and 33,000 miles.8. Which plot could be used to examine the association between two categorical variables?(a) Segmented Bar Chart(b) Histogram(c) Side-by-Side boxplot(d) Scatterplot9. The temperature in June in Los Angeles is is unimodal, symmetric, and mound-shaped with a mean of77 degrees and standard deviation of 5 degrees.What percent of days are colder that 87 degrees?Between what two temperatures do 68% of the days in Los Angeles fall between?We recorded a temperature of 59 degrees on June 5th. Is this unusual. Justify your answer?Name: Langholz Fall 201210. A study of breakfast cereals looked at the potassium content (in milligrams) and fiber content (in grams)of 77 different cereals. A linear model is appropriate and produced the following equation:dP otassium = 35 + 25 ∗ F iberA cereal has 3 grams of fiber in a serving. How much potassium do we predict it to have?The cereal actually has 99mg of potassium. What is the residual?The intercept says that a cereal with 0 grams of fiber has how much potassium?11. Consider the following plot and questions12. Which has more spread?Name: Langholz Fall 201213. A Pew Research poll from August/September 2010 asked respondents “Do you favor or oppose allowinggays and lesbians to marry legally?” The survey also collected information on the education level of theserespondents. The segmented relative frequency bar chart below shows the distribution of responses basedon education level.Is there an association between position on gay marriage and education level? Explain.14. Estimate the correlation coefficient for each of the four scatterplots below.Name: Langholz Fall 201215. The following histogram is of 77 athletes heart rates following a 5K race. Choose the statement that isthe best description of the dataset.HistogramHeart Rate (BPM)Count100 120 140 160 180 200 2200 5 10 15(a) Data is right skewed and the median and IQR best represent center and spread.(b) Data is right skewed and the mean and standard deviation best represent center and spread.(c) Data is left skewed and the mean and standard deviation best represent center and spread.(d) Data is left skewed and the median and IQR best represent center and spread.16. Again, consider the histogram of 77 athletes heart rates following a 5K race from above. Estimate themean. Provide a single number, not a range of values.17. Are there any outliers?18. A recent study, reported in the LA Times, found that the density of liquor stores in a neighborhood wasstrongly and positively correlated with the amount of crime. A scatterplot that plots crime rates againstliquor store density shows a fairly linear association. This means that (choose the best answer):(a) Neighborhoods with an above average amount of liquor stores tended to have a below average amountof crime.(b) Neighborhoods with an above average amount of liquor stores tended to have an above averageamount of crime.(c) If we could decrease the number of liquor stores in high-crime neighborhoods, the amount of crimewould decline.(d) There are no conclusions that can be made.Name: Langholz Fall 201219. Data recorded from 29 rollercoasters about total length in feet and speed in mph was recorded fromamusement parks all over the United States. The scatterplot shows a moderately strong, positive linearrelationship. The corresponding R2is 44.9%. Use the following information from the data recorded towrite the regression equation for predicting speed from length.Mean Standard DeviationSpeed 42.53 12.03Length 2072.35 977.42Interpret the slope in contextInterpret the intercept in contextGhost Rider is 4,533 feet long with a maximum speed of 56 mph. Do we have a positive or negativeresidual?Name: Langholz Fall 201220. To study the difference exercise makes on the grades of college students, a researcher desires to com-pare the GPA of students at randomly selected colleges across the United States. The researcher selectsstudents at random and after interviewing them to find out who exercises and who does not, chose 644students of each (exercisers and non-exercisers). The researcher made sure the two groups were similarin racial composition, gender, major, and ever every student had accumulated at least 120 units towardsgraduation.What is the “treatment”?What is the response variable or outcome of interest?Is this an