STATS$Final*Review*(S1)* 1) Which of these are categorical data? A. The birth weights of anteaters B. The lengths of anteaters C. The different types of anteaters D. The top speeds of anteaters E. The prices of anteaters 2) The relationship between two variables can be graphed using a(n) A. histogram B. dotplot C. stem-and-leaf plot D. scatter plot E. boxplot Use the stem-and-leaf plot for #3-5 Home Runs per team at midseason

7 | 1 7 8|5 represents 8 | 5 6 7 8 85 homeruns 9 | 0 1 2 5 9 10| 1 3 11| 1 12| 2 13| 0

3) What was the largest number of runs any team hit by midseason? 4) Which best describes the data? A. skewed; mean greater than median B. skewed; mean less than median C. symmetric; mean greater than median D. symmetric; mean equal to median E. symmetric with outliers 5) Find the median 6) Since the distribution of housing prices in a community is usually skewed right, which measure of center should you use for housing prices? A. Mean B. Median C. Mode D. Outlier E. None of the above 7) A distribution is skewed to the left and has a mean of $19. Which is a possible value for the median? A. $10 B. $18 C. $20 D. $29

8) In Block 1, the average for the exam was 85% for 19 students. In Block 2, the average was 89% for 17 students. What was the overall average for the two classes? A. 89% B. 87% C. 86.9% D. 85% E. not given enough information to calculate 9) If the average on a test was and 82 points with a standard deviation of 2.2, what would be the new mean and s.d. if the teacher added 5 points to everyone’s score? 10) Which statement is true given these box-plots comparing pulse rates before and after exercising?

A. The ranges of pulse rates are the same before and after exercise B. More than 50% of the pulse rates for before were less than the minimum for after exercise C. There was more variation in the middle 50% of pulse rates after exercising D. The pulse rates after exercising were always higher than before E. There were no outliers in either case 11) Which measure of central tendency and measure of variation should be used with a normally distributed distribution? A. The mean and standard deviation B. The mean and interquartile range C. The median and interquartile range D. The median and standard deviation E. The mode and interquartile range 12) What does a z-score of 2 mean for a test? A. You missed 2 questions B. You got twice as many right as average C. Your grade was 2 points above average D. Your grade was 2 s.d.s above average E. Your IQ is 2 points higher than “normal”

Use for #13-14: You measured the weights of members of population W and found the weights to be normally distributed, with a mean of 160 pounds and a standard deviation of 25 pounds.

13) For population W, find the z-score associated with a weight of 120 pounds. A. z = -2.6 B. z = -1.0 C. z = -1.6 D. z = 1.0 E. z = 1.6 14) Which is a reasonable estimate for the smallest weight in this population? A. 60 pounds B. 85 pounds C. 110 pounds D. 135 pounds E. 160 pounds 15) What area, to the nearest whole percent, of the normal curve is located between z = -0.6 and z = 1.4? A. 64% B. 91% C. 27% D. 50% E. 95% 16) Applicants to a college psychology department have normally distributed GRE scores with a mean of 544 and a standard deviation of 103. What percentage of applicants scored above 450 on the GRE? A. 82% B. –82% C. 26% D. 11% E. 1% 17) Using N(1500, 200) for the SAT test and N(21, 3) for the ACT, if Jocelyn got an 1800 on the SAT and a 27 on the ACT, on which test did she actually perform better? Explain.

Use for #18-19 You have the following regression equation for the effect of streetlights per block (x), on crimes per month (y):

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ˆ y = 2.4 − 0.2x

18) How many crimes a month are predicted when there are 7 streetlights on a block? A. 3.8 B. 1.7 C. 16.6 D. –11.6 E. 1.0 19) Calculate the residual for a block with 10 street-lights and 1 crime a month. A. –0.6 B. 0.6 C. –0.4 D. 0.4 E. –1.2 20) What is the correlation coefficient, r ? A. The strength of the relationship between any two variables B. The strength of the relationship between any two numerical variables C. The strength of the linear relationship between any two variables D. The strength of the linear relationship between any two numerical variables E. The proportion of variation of y accounted for by the model 21) If r = 0.78 for a set of data, how does this value change if each of the x-values are increased by 10? A. The new correlation coefficient will be 0.88 B. The new correlation coefficient will be 0.68 C. The correlation coefficient will not change D. There is not enough information to tell 22) Which determines the sign of r? A. The pattern of the residuals B. The strength of the relationship between variables C. Whether the y-intercept is positive or negative D. Whether the value of y increases or decreases as the value of x increases E. Whether the sum of the squared residuals is positive or negative

23) Find the error with this statement: The correlation between gender and age is 0.273 24) Suppose that all sample data points are on the same line with a positive slope. What would r be for this sample? A. –1.0 B. +0.99 C. +100 D. +1.0 E. same as slope of the LSRL 25) A value of r2 of 0.85 means: A. 15% of the variation in y is explained by the changes in x. B. 15% of the variation in x is explained by the changes in y. C. 15% of the variation in x isn’t explained by the changes in y. D. 85% of the variation in y is explained by the changes in x. E. 85% of the variation in x is explained by the changes in y. 26) True or False: An r of –1.0 proves a strong cause and effect relationship between x and y. 27) You’re going to test two new varieties of fish food vs. a commonly used fish food. You set up an experiment as follows: 60 fish are randomly assigned to each of three different tanks. One tank is randomly selected to receive one of the new foods, another to receive the other new food, and the third tank to receive the common food. Fish growth is measured over time. This is an example of: A. a randomized block design B. a double-blind matched pairs test C. a completely randomized design with no control group D. a comparative block design E. a completely randomized design with a control group

28) As primary research for one of her books, Shere Hite distributed 100,000 questionnaires to women’s groups: 4,500 women responded. Hite found that 96% of the women felt they give more emotional support to than they get from their husbands or boyfriends. Which of the following best describes her sample? A. Representative sample B. Voluntary response sample C. Stratified random sample D. Systematic sample E. Cluster sample 29) For a survey regarding the food in the cafeteria, every 20th student to arrive at school was interviewed. This is an example of: A. Simple random sampling B. Systematic sampling C. Cluster sampling D. Stratified sampling E. None of these 30) To determine whether extensive exercise lowers the resting heart rate, a study is performed by randomly selecting 10 employees from the 6 largest companies is the city and recording the hours exercised per week and resting heart rate for each. This is an example of a(n) A. experiment with a control group B. experiment with blocking C. observational study with little bias D. observational study with volunteer bias 31) To determine if the generic brand of pet food is better than the store brand, researchers randomly assign the generic brand to a group of 50 dogs and randomly assign the store brand to a group of 45 cats. Is this a good experimental design? A. Yes, because there was a control group B. Yes, because it was blocked by type of pet C. No, because more than two brands should have been tested D. No, because more than two types of pets should have been used E. No, because brand is confounded with type of pet 32) Why would it possibly be better to conduct an experiment rather than an observational study?

33) If subjects in an experiment are separated into groups of whites and non-whites prior to the random assignment stage, we should think of race as a (an): A. bias B. blocking variable C. matched pair D. explanatory variable E. response variable 34) Justin Hunter has an 80% chance of making his shot in a shoot-out. Which plan could be used to simulate the number of shots he would make in his next 3 attempts?

I. Let 1, 2, 3 represent making the first, 4, 5, 6 making the second and 7, 8, 9 making the third. Generate 3 random numbers, ignoring repeats II. Let 0, 1 represent missing a shot and 2, 3, …9 making a shot. Generate 3 random numbers and count how many are in 2-9, ignoring repeats III. Let 0, 1 represent missing a shot and 2, 3, …9 making a shot. Generate 3 random numbers and count how many are in 2-9 A. I only B. II only C. III only D. II and III E. I, II, and III 35) If you are dealt a hand of 5 cards, what is the probability that at least one is a heart? A. 0.222 B. 0.237 C. 0.763 D. 0.778 E. 0. 918 36) A standard 6-sided die is rolled. What is the probability that the number rolled is even or less than 4? A. 1 B. 0.83 C. 0.67 D. 0.5 37) Two events, A and B, are independent if A. P(A) = P(A|B) B. P(A U B) = P(A) + P(B) C. P(A) = P(B) D. P(A U B) = 1

38) A marketing survey indicates that 60% of the population owns an automobile, 30% owns a house and 20% owns both. What’s the probability of owning an automobile given that a family owns a home? A. 0.67 B. 0.50 C. 0.33 D 0.20 39) If P(A) = 7% and P(B) = 28%, find P(A U B) if A and B are mutually exclusive. A. 0.02 B. 0.21 C. 0.33 D. 0.35 40) Here are the results of a survey given to 100 students about whether they have seen the movies The Sandlot and Mean Girls.

! ! ! !!!!!!!!!Mean Girls

The Sandlot!! !

!

Based on the responses, what is the probability that a student has seen Mean Girls, given that he/she has seen at least one of the movies? A. 0.60 B. 0.67 C. 0.89 D. 0.90 This two-way table gives frequencies of the combined simple events of color and size of marbles in a bag. Use this for #41-42 Blue Yellow White Black S 27 34 16 10 87 M 7 19 53 13 92 L 3 0 11 42 56 37 53 80 65 235 41) What’s the probability that a randomly selected marble will be blue or white? A. 0.34 B. 0.16 C. 0.50 D. 0.18 E. None of the above 42) Find the probability of a randomly drawn marble being yellow, given that the marble is small. A. 0.39 B. 0.64 C. 0.14 D. 0.37 E. 0.23