1 1st Practice exam for EXAM 1 1) What can be concluded from the boxplot right? a) About 50% of the data values are larger than 88. b) About 50% of the data values are either larger than 94 or smaller than 80. c) About 50% of the data values are between 80 and 94 d) Two of the above are true e) All of the above are true. 2) A study was undertaken to determine if atmospheric pressure has an impact on plant heights. To study this, 20 Spartina alterniflora plants were planted at sea level while another 20 Spartina alterniflora plants were grown in a special chamber aboard the International Space Station, and the heights of the plants were recorded. The goal was to see if the plant heights were affected by the atmosph er ic pressure exerted on the plant. What are the variables, and what kind are they? a) Explanatory: Location (categorical) Response: Height of plant (numerical) b) Explanatory: Location (categorical) Response: Height of plant (categorical) c) Explanatory: Height of plant (numerical) Response: Location (categorical) d) Explanatory: Species of plant (categorical) Response: Height of plant (numerical) e) Explanatory: Species of plant (categorical) Response: Location (categorical) 3) Suppose you have the following 2 data sets. DATA SET A takes the values: 1, 2, 3, 3, 5, 7 , 8, 9, 17, 17, 22, 25 DATA SET B takes the values: 6, 7, 8, 8, 10, 12, 13, 14, 22, 22, 27, 30 Which of the following will be the same for both DATA SET A and DATA SET B? a) IQR and range will be the same b) Median and IQR will be the same c) Only the median is the same d) Only the IQR is the same e) None of the center and variability statistics are the same 4) In the figure at the right, the relationship between x and y can be described as a) Strong linear relationship b) Weak linear relationship c) Weak relationship d) No relationship e) None of the above are a good description of the relationship 68 72 76 80 84 88 92 96 100-4 -2 0 2 4-4 -2 0 2 4xy2 5) A study found that there is a large positive correlation between self‐esteem scores and performance in high school students. Which of the following can you conclude? Assume there are no outliers and the data indicates a linear relations hip exists between self‐esteem scores and performance. a) Raising self‐esteem improves performance in schools b) Better performance in schools causes higher self‐esteem c) Raising self‐esteem causes poorer performance in schools d) Lurking variables such as parental support may affect both self‐esteem and performance in school. e) Two of the above are equally good answers According to ESPN, LeBron James has a regular season free‐throw success rate of 75% over his playing career to date. Assume that the free‐throw shots are independent, that is, success or failure on one shot does not affect the chance of success on another shot. Use this information to answer the next two questions. 6) Consider 10 free‐throws taken by LeBron James, what is the probability that at least 8 of them are successful? a)    91 10010 100.75 0.25 0.75 0.25910 b) 82100.75 0.258 c)       82 91 10010 1 0 100.75 0.25 0.75 0.25 0.75 0.258910 d) 821010.750.258 e) None of the above 7) Consider 100 free‐throws taken by LeBron James, what is the probability that at least 80 of them are successful? Use the normal approximation if appropriate. Otherwise, choose e)? a) 0.1251 b) 0.8749 c) 0.6064 d) 0.3946 e) None of the above 8) Multiple drugs are often used in treating high blood pressure. Suppose 10% of people taking blood pressure medicine A experience negative side effects and 20% of people taking medicine B e xper ience negative side effects. If the side effects of the two drugs occur independently, what is the probability a person taking both drugs experiences at least one side effect? a) 0.28 b) 0.72 c) 0.30 d) 0.02 e) 0.98 3 9) A recent article in an educational research journal reports a positive correlation of +0.75 between math PSAT score and math aptitude. It also reported a negative correlation of ‐0.75 between math PSAT score and score on a math anxiety test. Which of the following interpretations is most appropriate? a) Both relationships’ are equally strong b) A correlation of +0.75 indicates a stronger relationship than a correlation of ‐0.75. c) A correlation of ‐0.75 indicates a stronger relationship than a correlation of +0.75. d) People with high math anxiety have low math aptitude and people with low math anxiety have high math aptitude. e) We can’t tell from the above information which relationship is stronger. Suppose that the yearly family income in a population is normally distributed with mean $25,000 and standard deviation $10,000. Use this information to answer the next 2 questions. 10) What is the probability that a randomly selected family has a yearly family income of more than $28,500? a) 0.350 b) 0.637 c) 0.363 d) 1.000 e) None of the above 11) Suppose that 6.30% of the population lives below the poverty level. What is the poverty level in this population? (The poverty level is the cu toff value, below which a family is considered to live in poverty.) a) $9,700 b) $28,300 c) $25,630 d) $1575 e) None of the above are close 12) In the 1990s, the average daily caloric intake of healthy female teenagers was normally distributed with mean 28.6 Kcal/kg and standard deviation 6.6 Kcal/kg. In 1998 a random sample of 9 bulimic females teenagers was selected whose mean caloric intake was 23.3 Kcal/kg. Which numbers given above are parameters? Which are statistics? a) Parameters: 28.6 and 6.6 Statistics: 23.3 and 9 b) Parameters: 23.3 and 9 Statistics: 28.6 and 6.6 c) Parameter: 28.6 Statistic: 23.3 d) There are no parameters. Statistics: 28.6, 6.6 and 23.3 e) Parameters: 28.6 and 6.6 Statistic: 23.3 4 Air traffic controllers monitor the flights of aircraft and help to ensure safe takeoffs and landings. In the US air traffic controllers are required to undergo periodic random drug testing. A urine test is used an initial screening test due to its low cost and ease of implementation. One such