AP Statistics Final
Customers at a local video store were observed form 8 PM until 10 PM on a particular Friday night and it was found that the mean numbers of videos rented was 2.1 videos with a standard deviation of 1.6. Which of these is a valid conclusion of this study? A) The mean number of videos rented on Friday nights throughout the city is approximately 2.1 videos B) The mean number of videos rented on Friday nights at this store is approximately 2.1 videos. C) As the number of customers increases, the standard deviation of the sample will approach the mean of the population D) The number of videos rented at this store for this sample has a mean of 2.1 videos with a standard deviation of 1.6 videos. E) The mean number of videos rented on any weeknight at this tore is approximately 2.1 videos.
D) The number of videos rented at this store for this sample has a mean of 2.1 videos with a standard deviation of 1.6 videos
A simple random sample of 100 adults in a particular suburb is chosen. Suppose that only 60% of those selected responded. Which of the following is correct? A) Since the original design was a simple random sample, the results are valid B) This is an example of a multi-stage sample C) The sampling frame does not represent the population D) The results may be affected by the non-response bias E) This is a cluster sample since the percentage of non-respondents is lose
D) The results may be affected by the non-response bias
If the person in a sample are chosen to meet the demographics of the population, the sample will be A) a quota sample B) a stratified sample C) a cluster sample D) a voluntary response sample E) a convenience sample
A) a quota sample
Let H=B(100, .3) and K=B(100, .6). Which of the following best dewscribes a comparison of H and K? I. UH > uk II. uh< uk III. oh> ok IV. oh < ok
B) II and IV
Which of the following statements can be inferred from the histogram? A) median = mean B) median < mean C) the data are skewed left. D) The data has to clusters.
B) median < mean
Part of a printout of a computer regression analysis of the effect of a change in a manufacturing process is shown. Output A represents the output of stations before the change and output b represents the output of the stations after the change. What conclusion can be drawn from this print-out?
C) The slop of the regression line is significant
A university anticipates that next year it will need to house 47% of its undergraduate students. The student newspaper conducts a random sample of 50 freshmen, sophomores, and juniors who claim to be returning next ears and finds that 57% of the students indicate that they would need housing from the university. Which of the following tests would be most appropriate for establishing that the university should increase their estimate? A) t-test of means B) one-sample proportion z-test C) matched pair t-test D) one-sample proportion t-test E) chi-square test
B) one-sample proportion z-test
In determining ratings of TV shows, a rating company gathers data on many variables. Which of these is categorical? A) age of viewers in years B) family income of viewers C) gender of viewers D) number of TVs in a household E) number of hours TV is watched
C) gender of viewers
The residual plot of a linear regression is shown below. An appropriate next step in the analysis would be to A) implement a transformation to find an exponential model B) implement a transformation to find a power model C) implement a transformation to find a quadratic model D) implement a transformation to find a logarithmic model E) stay with the linear regression but eliminate outliers
C) implement a transformation to find a quadratic model
Which of the follwoing graphs represents a normal distribution with a mean of 40 and a standard deviation of 8?
The low one centered at A
Randomization A) is necessary in all experimental designs B) is not required in block design C) is not required in match pair designs D) is for simple random samples E) reduces the error in the estimate of the mean
A) is necessary in all experimental designs
Random digit tables and random number generators follow which of the following distributions? A) uniform B) chi-square C) normal D) t E) binomial
A) uniform
The following table displays the results of a sample of 99 sports fans in which the subjects indicated their favorite sport of three listed. The data are organized by favorite sport and age group. What is the probability that a person chosen at random will be over 40 if he or she favors football? (15 are over 40 and like football, and 43 total like football)
15/43
Suppose the least squares regression line of the set {(hours of part time work per week, GPA)} for 1,000 high school seniors was GPA= 3.21 - .04(hours). The average GPA of students who worked 20 hours per week is approximately A) 2.41 B)2.55 C) 2.8 D) 2.1 E) the value cannot be determined
A) 2.41
A residual plot of a linear regression provides evidence of a good fit if which of the following statements are true? I. The points are randomly scattered above and below the horizontal axis II. The distances from the horizontal exis to the [oints are approximately the same. III. The values of the deviations form the horizontal are small. A) I only B) I and II only C). I, II, and III D) II only E) II and III only
A) I only
Consider the binomial distribution binomial(20, .4). If we wish to calculate P(x greater than or equal to 16) for this binomial distribution, we could do which of the following? I. Calculate the sum of P(16), P(17),..., P(20) in binomial(20, .4) II. calculate P(x greater than or equal to 15.5) in Normal(8, square root of 4.8) III. calculate P(x greater than or equal to 16) in normal(8, square root of 4.8) A) I only B) I and II C)I and III D) I, II, and III E) II only
A) I only
Which of the following is resistant to extremes values? I. Mean II. Median III. mode IV. range A) II, III B) I, II, IV C) II, III, IV D) II only E) all are resistant to extreme values
A) II, III
If a data set is transformed using (x,y) -> (ln x, ln y) and least squares regression is performed on the transformed set, then the resulting regression model, relative to the original data, will be A) a power mode B) an exponential model C) a quadratic model D) a linear model E) a logarithmic model
A) a power model
The scatterplot displays the ages and weights of a set of adults in a small manufacturing company. Which of the following best represents the distribution of the ages of the respondents displayed in the scatterplot? (appears to be no particular pattern in plot) A) bar graph with almost even values from 25-45 B) bar graph with significantly more values in the 25 level C) stem/leaf plot D) box plot E) none of these represents the distribution of the ages of the respondents
A) bar graph with basically even values
Which of the following conclusions is inappropriate based on this plot of the population? A) the data are approximately normal B) the data are discrete C) The mean is approximately equal to the median D) the mean is approximately 50 and the standard deviation is approximately 15 E) all of these are appropriate
A) the data are approximately normal
If 10 is added to every value of a data set, which of the following occurs? A) the mean increases by 10 B) The median remains the same C) the range increases by 10 D) the mode increases by square root of 10 E) The mean increases by 100
A) the mean increases by 10
A symmetric, mound-shaped distribution has a mean of 42 and a standard deviation of 7. Which of the following is true? A) There are more data values between 42 and 49 than between 28 and 35 B) It is impossible that the distribution contains a data value greater than 70 C) Approximately 95% of the data lie between 35 and 49 D) The interquartile range is approximately 14 E) the median of the data is more than 42
A) There are more data values between 42 and 49 than between 28 and 35.
Which of the following plots is least useful in determining the shape of a distribution?' A) box plot B) Stem plot C) histogram D) Dot plot E) Bar graph
A) box plot
A study to determine the existence of a relationship between the number of students and number of teachers in 30 high school s in a particular state yielded the regression equation Teachers= 0.2 + 0.27(Students) with a correlation coefficient of 0.73. Which of the following is a correct conclusion? A) This equation predicts the number of teachers accurately 73% of the time B) The student-teacher ratio in the schools studied was 0.27 C) An increase of 30 new students would motivate the hiring of one new teacher D) The association between number of students and number of teachers is positive E) A drop in student enrollment will result in the dismissal of one or more teachers
D) The association between number of students and number of etachers is positive
Which of the following is the reason that the tests for difference of proportions and difference of means include a requirement of independent samples? A) the sample proportions or means could be skewed if the samples were not independent B) the tests do not apply to samples from the same population C) the samples will not be simple random samples unless they are independent D) Variances from independent samples can be combined easily whereas variances from dependent samples are not as easily combined E) none of these is the reason for this requirement
D) Variances from independent samples can be combined easily whereas variances from dependent samples are not easily combined
Consider the experiment of rolling two dice and adding up the outcomes. To find the probably lite that a 7 will come up before a 4 does, you should use which of the following? A) permutations B) combinations C) conditional probability techniques D) geometric probability techniques E) binomial probability techniques.
D) geometric probability techniques
Two antifreezes are to be tested for minimum temperature ratings. Sixteen ounces of antifreezes A and B are placed in a freezer and the amount of liquid is measured after 15 minutes of exposure to various temperatures. The data were (chart) Which of the following principles of design was not present in the experiment? I. comparison II. randomization III. replication A) I only B) II only C) III only D) I and II E) II and III
E) II and III
If 10 is added to the maximum value of a large data set, which of the following occurs? A) the mean increases by 10 B) the median remains the same C) the range remains the same D) the mode increases by the square root of 10 E) the mean increases by 100
B) the median remains the same
Which of the following is not a consideration in determining the goodness of a fit of a model? A) the value of r squared B) the slope of its residual plot C) the existence of influential points D) the existence of a pattern in the residual points E) the existence of outliers
B) the slope of its residual plot
One of your peers claims that boys do better in math classes than girls. Together you collect two independent simple random samples and calculate the given summary statistics of the boys and girls for comparable math classes. In Calculus, 45 boys had a mean percentage of 82.3 with standard deviation of 5.6 while 42 girls had a mean percentage of 81.2 with standard deviation of 6.7. Which of the following would be the most appropriate test for establishing whether boys do better in math classes than girls? A) two-sample z-test for means B) two-sample t-test for means C) chi-square test D) two-sample z-test for proportions E) none of these tests would be appropriate
B) two-sample t-test for means
A sample space contains only 5 elements. Which of the following could not be its probability distribution? Assume that the sets of the probabilities correspond to the elements V, W, X, Y, and Z. A) {.3, 0, ,3, 0, .4} B) {.1, .2, .3, .4, .1} C) {.9, .05, .05, 0, 0} D) {0, 0, 0, 0, 1} E) {.2, .2, .2, .2, .2}
B) {.1, .2, .3, .4, .1} (adds up to more than 1)
In a game of roulette, there are 18 red numbers, 18 black numbers, and 2 green numbers. You may bet on red or black, but not green. If you win a $1 bet on the color, the house pays you $1. What is the expected value of each $1 you you play at this game? A) -$.50 B)-$.10 C)-$.05 D) -$.01 E) $0
C) -$.05
Ina particular game of solitaire, stacks of cards are combined if their top cards have either the same suit or the same numerical value. The lead stack is moved either one to the left or three to the left according to these rules. The goal of the game is to end up with a single large stack of cards. If you play this game 10 times, your net winnings should be approximately A) -.48 B) -.12 C) .43 D) .74 E) .91
C) .43
Two investigators are arguing over what estimate to use to calculate the sample size for a study that they wish to conduct of a population proportion. They have agreed to the same margin of error and the same confidence interval. However, investigator A wishes to use .30 for the estimated sample proportion based on his analysis of previous studies while investigator B wishes to use .41 as the estimate based on her analysis of the earlier studies and some evidence regarding trends in their industry. What is the ratio of the sample size of investigator A to the sample size of investigator B?
C) .868
A CEO of a small corporation wishes to hire your consulting firm to conduct a simple random sample of its customers to determine the proportion that consider her company as their primary source of product. She tells your staff that she requires that the margin of error be no more than 3% with 95% confidence. Earlier studied have indicated that the approximate proportion is 37%. Using the CEO's research, your staff calculates that a sample size of 995 or more will meet her requirements. By how many more people would you increase the sample size if you use the most conservative estimate of the sample proportion? A) 12 B) 52 C) 73 D) 112 E) 1068
C) 73
Which of the following is false about the correlation coefficient? A) -1 is less than or equal to r which is less than or equal to 1 B) If r is negative, an inverse relationship is indicated C) A one-to-one relationship will have r >1 D) If the data set contains two points, the r= -1, 0, 1 or undefined E) A value of r= .2 indicates a weak linear relationship
C) A one-to-one relationship will have r>1
Suppose a bivariate set of data {(heights, weights)} of 250 adult women had a correlation coefficient of 0.6. Suppose a woman had a height that was 1 standard deviation above the average height of the women in the set. Her predicted weight will be A) 1 standard deviation above the weight of the women in the set B) greater than 1 standard deviation above the weight of the women of the set C) less than 1 standard deviation above the weight of the women in the set D) approximately equal to the average height of the women of the set E) the value cannot be determined
C) Less than 1 standard deviation above the weight of the women of the set
Which of the following can be inferred from this cumulative frequency histogram of ages of residents in a n apartment building in a local suburb? (frequency raises steadily with age) A)The median age is about 60 B) The median age is baout 20 C) The interquartile range is about 37 D) This building tends to appeal to tenants under 30 E) This building tends to appeal to tenants over 70
C) The interquartile range is about 37
At a particular value, the residual for a linear regression has a value of 1.2. Which of the following is a true statement? A) r squared = .85 for the regression B) The regression line overestimates the actual value at this point C) the regression line underestimates the actual value at this point D) A non-linear regression would provide a better fit. E) none of these is true
C) The regression line underestimates the actual value at this point
The length of a wait at a drive-up ATM can be best described as A) a categorical variable. B) an infinite discrete variable. C) a finite continuous variable D) a statistic E) a parameter.
C) a finite continuous variable.
A test is conducted to determine if a a random sample of 100 fish whose mean length is 53 centimeters provides evidence that the expected mean length of 50.5 centimeters is low. The P-value of the appropriate test is .072. This P-value represents the probability that A) the corresponding confidence interval captures the expected mean of 50.5 B) the sample result causes an error in the expected result C) a sample of size 100 would have a mean of 53 centimeters or more when the true mean is 50.5 cm D) a sample of size 100 would provide a more accurate mean than the expected value of the mean. E) the expected mean length of 50.5 centimeters is low
C) a sample of size 100 would have a mean of 53 cm or more when the true mean is 50.5 cm
Which of the following is a valid probability density function on the interval [0,1]? A) f(x)= .5x B) f(x)=x C) f(x) = 2x D) f(x)= 3- 1.5x E) f(x)= x-1
C) f(x) = 2x
Which of the following follows from the Central Limit Theorem? A) For a large n, the population is approximately normal B) For any population, the sampling distribution is approximately normal, regardless of sample size C) For a large n, the distribution of sample means is approximately normal, regardless of the shape of the population D) For any sample size, the distribution of sample means is approximately normal E) None of these follow from the Central Limit Theorem
C) for a large n, the distribution of sample means is approximately normal, regardless of the shape of the population
A two way table relates the favored country of origin of car and the income of a set of 100 respondents of a survey. If a x squared test of independence indicates a significant result, which of the following is not a valid fat about the test? A) the null hypothesis of the test is that the variables are independent B) the x squared test is, by definition, one-tailed C) the degrees of freedom of the test are found by multiplying the rows of the table and the columns of the table D) the calculated value of x squared must exceed the critical value of the x squared distributions of the appropriate number of degrees of freedom in order for the test to be significant E) all of these statements are valid
C) the degrees of freedom of the test are found by multiplying the rows of the tabl0 eand the columns of the table
As sample size increases, if all other information stays the same, which of the following statements is reasonable regarding the calculation of a confidence interval? A) the margin of error increases B) the margin of error stays the same C) the margin of error decreases D) the confidence level increases E) the confidence level decrease
C) the margin of error decreases.
Causation cannot be inferred for A) valid randomized block designs B) valid completely randomized designs C) Valid observational studies where n is large D) valid matched pairs designs E) any statistical study
C) valid observational studies where n is large
Which of the following is false about the standard deviations? A)For mound-shaped, symmetric distributions, approximately 68% of the data are within 1 standard deviations of the mean B)For Mound-shaped symmetric distributions, approximately 95% of the data are within 2 standard deviations of the mean C)Standard deviation cannot be computed for skewed distributions D) Standard deviation is the square root of variance E) For mound-shaped, symmetric distributions, the interval [-1 standard deviation, +1 standard deviation] is wider than the interquartile range
C). Standard deviations cannot be computed for skewed distributions.
Which of the following items is not important when applying the Central Limit Theorem to the distribution of sample means in the case of a large sample? A) the mean and standard deviation of the population B) the mean and standard deviation of the sample C) the shape of the sampling distribution D) the shape of the population distribution E)All of these are important when working with the Central Limit Theorem
D) The shape of the population distribution
A test of independence for data organized in a two-way table relating number of siblings and number of family relocation is conducted using the chi-square distribution. The P-value of the test is .045. If alpha = .05, then which of the following is a valid conclusion for the test?
D) We have sufficient evidence to reject the hypothesis that the variables are independent.
In the regression equation y=b0 + b1x, which of the following statements about b0 is always true? A) b0 is the x intercept of the regression line B) b0 is the value of response variable when the explanatory variable has a value of 0 C) b0 provides important contextual information about the relationship between the variables D) b0 depends on the values of b1, x bar and y bar E) all of these are always true
D) b0 depends on the values of b1, x bar, and y bar
The statement below can be made true b adding which of the following? "The median of a distribution is approximately equal to the mean of the distribution ________________." A) for all distributions B) only for symmetric, mound-shaped distributions C) for skewed distributions D) for symmetric distributions E) for mound-shaped distributions
D) for symmetric distribution
If it is anticipated that answers to a survey of high school students may be affected by the class standing of the respondents, which of the following sampling designs is appropriate? A) simple random sample B) systematic sample C) quota sample D) stratified random sample E) voluntary response sample
D) stratified random sample
Suppose we graph two normal distributions, A and B, on the same axis. If the mean of a= 50 and the standard deviation of a =18, and the mean of B is 50 and the standard deviation of B is 12. Which of the following will not be true of the graphs of A and B? A) The graph of B has a larger maximum value than the graph of A B) Both graphs are centered at x=50 C) The area under the graph of B equals the area under the graph of A D) the domain of the graph of A is larger than the domain of the graph of B E) All of these are true
D) the domain of the graph of A is larger than the domain of the graph of B
Which of the following will not be a cause of response bias? A) honesty of the respondent B) wording of the questions C) appearance of the interviewer D) the method of the selection of the participants E) the time when the questions were asked
D) the method of selection of participants.
A teacher wishes to calculate the margin of error for the estimate of a population mean based on a sample size 20 from a normal population. If she is to use the formula involving the t-distribution, which quantity is required in order for her to use this formula? A) the appropriate critical z-value B) the null hypothesis C) the alternative hypothesis D) the sample standard deviation E) the mean of the population
D) the sample standard deviation
Which of the following best describes the difference between a standard simulation and a wait-time simulation? A) the wait-time sirmulation takes longer since you must wait for the occurrence of interest. B) random digit charts cannot be used for wait-time simulations C) a wait-time simulation is not as accurate as a stand simulation D) technology cannot be use for wait-time simulations E) all are correct
E all are correct
Which of the following is not categorical? A) hair color B) eye color C) athletic jersey number D) numbers in street adress E) All of these are categorical
E) All of these are categorical
Which of the following is not possible? A) the standard deviation is greater than the mean B) the 5-number summary has 3 identical values C) The mean is negative and the standard deviation is positive D) The interquartile range is equal to the range E) All of these are possible
E) All of these are possible
An outlier in a linear regression is identified by which of the following criteria? A) the coordinates are outliers in the x- and y-data sets B) the coordinates are outliers in the y-data set only C) The point is also an influential point D)The distance to the grand mean is very large relative to other data points E) The corresponding residual is large compared to the residuals of other data points
E) The corresponding residual is large compared to the residuals of the other data points
It has always been thought that of the three major radio stations that service a large metropolitan area, Station A had a 30% share of the market while stations B and C each enjoyed a 35% market share. A study of 75 randomly chosen radio listeners indicated that 30 people listen to station A, 25 listen to station B, and the rest listen to station C. Which of the following tests would be more appropriate in establishing that the market shares have changed? A) t-test of means B) two-sample proportion z-test C) matched pair t-test D) two-sample proportion t-test E) chi- square test
E) chi-square test
Which of the following scatterplots will have a correlation coefficient near 0? A) positive linear slope B) negative linear slope C)negative, more linear slope D) a U curve E) none of these appears to have a correlation near 0
E) none of these appears to have a correlation near 0
If r is close to 0, which of the following must be true? A) there is no association between the variable B) the scatterplot shows no pattern C) there is at least one outlier D) the residual plot shows a pattern E) none of these must be true
E) none of these must be true
What is the expected value of the discrete probability given in the table below? (probabilities add up to more than 1)
E) this is not a valid probability distribution
A linear regression model from a study of weight loss and daily exercise time was Weight loss= -0.63 +0.29(time). This indicates which of the following? A) The correlation coefficient is negative B)If you exercise longer, you will lose more weight C) You may gain weight if you don't exercise D) (0, -0.63) is an outlier E)Weight loss and exercise time are positively related
E) weight loss and exercise time are positively related
Which of the following is always true of a discrete variable? A) discrete variables have finite domains B) discrete variables cannot have negative values C) consecutive values of discrete variable differ by a fixed (constant) amount. D) Discrete variables can describe a day of the week E) discrete variables can be added.
E). Discrete variables can be added.
Which of the following describes a correct effect on the width of a confidence interval? I. As sample size increase, the width of the confidence interval decreases II. As the confidence level increases, the width of the confidence interval increases III. As the standard error of the estimate increases, the width of the confidence interval increases. A) I only B) II only C) I and III D) II and III E) I, II and III
E). I, II and III
In an experiment in which there are three factors with three levels each, what is the maximum number of treatments that may be studies? A) 3 B) 6 C) 9 D) 21 E) 27
C) 9
The probability density function for a uniform distribution on the interval [0,4] equals A) .004 B) .04 C) .4 D) 4 E) None of these
E) None of these
Blocking is a technique used to A) assist with random selection B) reduce variation within experimental groups C) create stratified sample groups D) isolate the effect of the treatment E) none of these
B) reduce variation within the experimental groups
A new grading program implemented in a high school gathers data on a number of items. Which of the following is categorical? A) number of periods absent? B) subject with the highest grade C) total number of points in a math course D) GPA E) number of credits earned
B) subject with highest grade
A pretzel company calculated that there is a mean of 72.5 broken pretzels in each production run with a standard deviation of 7.1. If the distribution is approximately normal, find the probability that there will be fewer than 60 broken pretzels in a run. A) 0 B) .04 C) .06 D) .10 E) .13
B) .04
A bivariate data set is transformed using (x,y) -> (x, ln y). If the correlation coefficient of ln y= b0 + b1x is 0.6, then the value of r squared for the exponential model of the original data is approximately A) 0 B) 0.360 C) 0.6 D) e to the 0.6 power E) 1.825
B) 0.360
Suppose the bivariate set of data (weight, mpg) for 30 domestic cars has the following statistics: smpg= 4.1 mi/gal and r= 0.90. If the least squares regression model is mpg= 12.7 + .01 (weight), then sweight is approximately A) 310 lbs B) 369 lbs C) 410 lbs D) 560 lbs E) 578 lbs
B) 369 lbs
Which of the following should be considered when evaluating the goodness of fit? I. Value of r squared II. residual plot III. y-intercept of the regression equation A) I only B) I and II C) II only D) III E) all of these
B) I and II
Suppose a data set of (numbers of hours of study, semester average) has a scatterplot like the one below. Which of the following transformations should we consider as good candidates to linearize data? (graph shows a roughly positive linear relation) I. (x,y) -> (x, y squared) II. (x,y) -> (x, ln y) III (x,y) -> (x, e to the y power) A) I only B) II only C) I and III D) II and III E) I, II, and III
B) II only
Give the correct order of the following from least to greatest I. 3rd quartile II. value at 70th percentile III. value with a z-score of 1 A) I, II, III B) II, I, III C) III, II, I D) I, III, II E) III, I, II
B) II, I, III
Which of the following best describes a type I error for a hypothesis test? A) It is the probability of accepting H0 when H0 is false B) It is the probability of reject H0 when H0 is true C) It is the complement of a Type II error D) It is the complement of the power of the test E) None of these describes a Type I error
B) It is the probability of rejecting H0 when H0 is true
A random sample of 100 engineers in a large consulting firm indicated that the mean amount of time they spend on leisurely reading each week is 1.4 hours with a standard deviation of 4.78. Using thsee sample statistics and different confidence levels, three interns independently calculate confidence intervls sfor the true mean amount of time all of the engineer in the company. THe confidence intevals of the interns were x: (.17, 2.63), Y: (.46, 2.54); Z: (.61, 2.19). Which conclusion is valid? A) All are calculated correctly with different levels of confidence B) only X and Z are calculated correctly C) Only X and Y are calculated correctly D) Only Y and Z are calculated correctly E) None of these intervals were calculated correctly
B) Only X and Z are calculated correctly
A girl scores a 23 in math on the ACT and 560 on the SAT. Supposed both distributions are approximately normal and the mean of the ACT was 19 with a standard deviation of 6 while the mean of the SAT was 490 with a standard deviation of 140. Which of the following is true? A)Comparison of z-scores will not identify the better score B) The number of students who took each exam will not impact the comparison of scores C) The z-score of the ACT score is .5 while the z-score of the SAT is .67 D)Comparison of percentiles will not identify the better score E)The raw scores cannot be compared since the difference in the means of the test scores is very large
B) The number of students who took each exam will not pact the comparison of scores
A distribution of weekly sales has a mean of $500.00 with a standard deviation of 230. Which of the following can be concluded from this information? A) the distribution is mound-shaped and symmetric B) negative Z-score would correspond to a value less than $500.00 C) some weekly sales were negative. D) Approximately 95% of the weekly sales were between $40.00 and $960.00 E) a weekly sale greater than $730 is more likely than a weekly sales less than $270.
B) a negative z score would correspond to a value less than $500.
The weight of a box of crackers labeled "Net wt. 1 pound/16 ounces" has been found to be uniformly distributed on the interval of [ 15.1 ounces, 16.4 ounces]. Which of these best approximates the probability that a box chosen at random will weight more than one pound?
D) .308
If the expected value of successes in a binomial experiment of 100 trials is 55, the standard deviation of the number of successes is approximately A) .05 B).83 C) 2.49 D) 4.97 E)24.75
D) 4.97
The following table displays by gender the number of people in a bridge club who favor a particular political party If we were to do a chi-square test, which expression woul dcalculate correctly the expected count of the number of males who favor the Democratic Party?
D) 50/205 x 105
The following table displays the results of a sample of 99 sports fans in which they indicated their favorite sport of three listed. The data are organized by favorite sport and age group. (chart) What is the probability that a person chose at random will be under 20 if he or she favors baseball? (7 fit in 20 & under and baseball, and there are 26 total baseball fans) A) 7/24 B) 30/99 C) 24/99 D) 7/26 E) 7/99
D) 7/26
A least squares regression line was determined from a study of car performance. The equation was mpg=33.06 - 0.05hP, where mpg is miles per gallon and hP is horsepower. What is a valid and reasonable conclusion from this regression? A) a car with no horsepower will bet 33.06 mpg B) horsepower and miles per gallon are directly related C) if you increase the horsepower, you will increase miles per gallon. D) high horsepower has a negative impact on miles per gallon. E) every unit increase in horsepower has a negative impact on miles per gallon
D) High horsepower has a negative impact on miles per gallon
Which of the following data sets has a correlation coefficient of -1? I. {(3,7), (5,5)} II. { (2,5), (3,18), (-6, -19)} III. { (x, y) | y=2 - 4x|
D) I and III
The probability that any individual catches a cold during the month of January is estimated to be .15. Assume that each person represents an independent experiment in which the probability of catching a cold is .15. Which of the following can be used to calculate the probability that no more than 3 out of 20 people will catch colds this January?
D) P(0) + P(1) +P(2) + P(3) where x ~binomial(20, .15)
Which of the following is true of any normal curve? A) it is centered at 0 and has a standard deviation of 1 B) it is symmetric with respect to the y-axis C) there are points of inflection at plus and minus 1 D) The area under the curve equals 1 E) all of these are true
D) The area under the curve equals 1.
A teacher has two sections of AP Statistics. On the last test out of 100 points, Class A had a mean of 75 with a standard deviation of 10. Class B had a mean of 82 with a standard deviation of 7. Which of the following is necessarily true? A) The highest score of all students combined is 78.5 B) The highest score in Class B is greater than the highest score in Class A C) The range of Class A is greater than the range of Class B D) The number in each class must be known in order to compute the mean of the combined classes E) The distribution of score for Class A is skewed right
D) The number in each class must be known in order to compute the mean of the combined classes
