AP stat lyfe :)))))))))
One card is randomly selected from a standard 52-card deck. Which of the following gives the probability that the card is a black ace?
(1/2)(1/13)
Suppose you roll a fair, standard six-sided die 10 times. What's the probability of getting exactly three fives in those 10 rolls?
0.155
If you randomly select one woman, what's the probability that she does aerobics?
0.169
Find the z-score for the lower quartile of any normal curve. Round your answer to the nearest hundredth.
-0.67
X -1 1 10 P(X) 25/36 10/36 1/36 What is the expected value of X?
-5/36
For population W, what is the percentile for the weight 160 pounds?
. 50th percentile
If you randomly select one person from the study, what would be the probability that he or she plays baseball?
0.0693
The conditional distribution of temperature by above average crime rate is:
0.12, 0.56, 0.33
The probability that a given 80-year-old person will die in the next year is 0.27. What's the probability that exactly 10 of 40 80-year-olds will die in the next year?
0.1385
Calculate the probability that the sum of the two dice is greater than or equal to 20
0.194
The relative frequency of students who study 5 - 6 hours a day is:
0.223
Estimate the relative frequency of countries with 20 - 22 days of no rainfall in the month of January.
0.32
You have two specially created dice. Each die has six sides. The first die has the numbers {1,3,5,7,9,11) on the sides. The second die has the numbers {2,4,8,10,11,15} on the sides. You're about to roll only the second die. Estimate the probability of getting an odd number on a single roll of this die.
0.333
The marginal distribution for crime rate (below, normal, above) is:
0.34, 0.37, 0.29
For a uniform distribution defined on (0 ≤ x ≤ 20), find P(x < 2 or x ≥ 15).
0.35
Find the probability of a randomly drawn marble being yellow, given that the marble is small.
0.39
The following table is for a discrete probability distribution. x 7 3 9 11 15 p 0.05 0.10 0.15 ? 0.25
0.45
What's the probability that a randomly selected marble will be blue or white?
0.50
In population W, what is the probability that a randomly selected subject will weigh between 140 and 180 pounds?
0.576
Calculate the residual for a block with 10 streetlights and 1 crime a month
0.6
The cumulative relative frequency of students who study 4 hours or fewer a day is:
0.615
The probability that a given 80-year-old person will die in the next year is 0.27. What's the probability that between 10 and 15 (inclusive) of 40 80-year-olds will die in the next year?
0.6191
Calculate the correlation coefficient.
0.6708203932
If you randomly select one man, what the probability that he doesn't do exercise walking?
0.769
Find the probability of a randomly drawn marble being large or small, given that the marble is black.
0.80
Consider a complete table of relative frequencies. The sum of the relative frequency column in such a table must be:
1
You take a 100-question multiple-choice test. Each question has five choices, and you guess at each question. Which of the following calculator commands would give you the probability of getting at least 30 questions correct?
1 - binomcdf(100,0.2,29)
How many crimes a month are predicted when there are 7 streetlights on a block?
1.0
You're given some bivariate (x,y) data. You use your calculator to find the linear regression line for the transformed data (ln x, ln y). Your calculator reports the equation of the least squares regression line to be Y = 0.2 + 0.4x. When x = 2, the correct predicted value for y is:
1.6117
How many fewer home runs did the team with the fewest home runs in the American League have than the team with the fewest home runs in the National League? How many more home runs did the team with the highest home runs in the American League have than the highest team in the National League?
14, 33
If you randomly select one man, what's the probability that he hunts, expressed as a percentage?
16.97%
Give, in millimeters, a minimum and a maximum thickness that will include 95% of the population of bolts.
19.98 to 20.02 millimeters
Give, in millimeters, a minimum and maximum thickness that includes 68% of the population of bolts
19.99 to 20.01 millimeters
You have two normally distributed populations: Population A: Mean = 50 Standard deviation = 12 Population B: Mean = 75 Standard deviation = 15 The area under the normal curve is greatest in which scenario?
Area above 80 in Population B
What is the interquartile range for the data in the table?
25.5
. Based on the data in the table, what is the largest number of births in a month you could possibly have and still have a lower outlier?
255
To the nearest whole number, what percentile is associated with z = -0.68?
25th percentile
What is the lower quartile for the data in the table?
294
The following hypothetical data set shows the purchase price (in thousands) for a sample of 3- bedroom, 2-bathroom homes in Essex County, MA over the past year. Compute the five-number summary and create a modified box plot. How many outliers are present in this distribution?
3
What is the variance of X?
3.73
What is the median for the data in the table? (Baby birth month)
306.5
What is the upper quartile for the data in the table?
319.5
Consider two discrete, independent, random variables X and Y with μX = 3, 2 X = 1, μY = 5, 2 Y = 1.3. 147. Find 2 36X .
36
You have two specially created dice. Each die has six sides. The first die has the numbers {1,3,5,7,9,11) on the sides. The second die has the numbers {2,4,8,10,11,15} on the sides. 125. If you roll the two dice, how many possible outcomes (not necessarily unique) are there?
36
Calculate, to the nearest whole number, the sample standard deviation of this data set, which is a sample from a larger population: {71, 75, 65, 73, 69, 77, and 67}.
4
Random variable X has 12 values with a mean of 8 and a standard deviation of 3. Random variable Y also has 12 values, but it has a mean of 11 and a standard deviation of 2. A new random variable Z is created as follows: Z = 2X + 3Y. 145. What is the mean of Z?
49
Using the empirical rule, you can assume that what percent of the normal distribution is outside two standard deviations of the mean in both directions?
5%
Consider these eight observations: {11,6,2,5,8,4,4,9}. What is the median?
5.5
In a binomial distribution with n = 140 and p = 0.62, what is the expected standard deviation of the distribution, to the nearest hundredth?
5.74
In a binomial distribution with sample size n = 65, and probability of success p = 0.8, what would be the approximate mean of the distribution?
52
Consider these eight observations: {11,6,2,5,8,4,4,9}. What is the mean?
6.125
.What percentage of applicants scored between 500 and 700?
60%
Find the GRE score at the upper quartile, Q3.
613
What is the GRE score at the 77th percentile?
620
What area, to the nearest whole percent, of the normal curve is located between z = -0.6 and z = 1.4?
64%
In population H, what is the height, to the nearest tenth of an inch, of the 70th percentile?
67.3 inches
What percentage of applicants had a GRE score below 625?
78%
Find μX+Y and σX+Y.
8, 1.52
What percentage of applicants scored above 450 on the GRE?
82%
A bivariate scatterplot has an r2 of 0.85. This means:
85% of the variation in y is explained by the changes in x.
To the nearest whole number, what percentile is associated with z = 1.2?
88th percentile
Consider a normal distribution with = 65 and = 4. A sample of size 950 is drawn from this population. Approximately how many of the 950 cases would you expect to find between 57 and 73?
903
You've computed the following least-squares regression line using a sample of college students: y= 55+5x , where x = hours of study per day and y = test score (ranges from 0 to 100). 84. Using this equation, which is the predicted test score for an individual who studies 8 hours a day?
95
Many statisticians say that the US Census, which attempts to count every population member directly, is significantly less accurate than a count estimated by random sampling. Why might a count estimated from random samples be more accurate than a census?
A census often can't find every population member, so some groups (such as the homeless) are often under-represented.
Which of the following situations satisfies all the conditions of a binomial setting?
A jar contains 500 balls - 300 red and 200 white. Ten balls are randomly selected from the jar with replacement, and the number X of red balls is recorded.
A symmetric distribution can't have which of the following characteristics?
A long tail on one side
Which of the following statements is correct?
A random variable must have a number as its value.
A survey is conducted at a local mall. An interviewer stops every 20th person that walks by and asks them to answer some questions about attitude on transportation use. Of the 200 individuals who complete the survey (all of the people asked completed the survey), 80 say they prefer the bus as a transportation option. From this analysis, you have reason to conclude that:
About 40% of the mall goers prefer the bus as a transportation option
Why is the IQR considered to be a resistant statistic?
Adding a new extreme observation has little effect on it.
Which of the following would most likely be graphed as a bar chart rather than a histogram?
All of the above
A normal curve table tells you that the probability lying below z = -1 is 0.1587. This can be interpreted as:
All of the above.
Consider a random experiment with S = {a,b,c,d,e,f,g}. The event B is composed of simple events {c,e,g}. Which of the events below is mutually exclusive with event B?
All of the above.
Which league has the team that had hit the most home runs by midseason, and how many home runs had that team hit? Which league had the team with the fewest home runs?
American, 149, American
Which of the situations below probably does not have a lurking variable operating in some way?
Beaches with more sand than rocks tend to be older
Create a modified box-and-whisker plot for each of the three data sets. Then use the plot and the values of the five-number summary to answer the following question: Which team has the greatest variation in the points per game for the middle 50% of their observations?
Boston
.The median points per player per game for each team are:
Boston = 9.65; Chicago = 8.9; Seattle = 8.3.
Assume that normal curve A and normal curve B have identical population means. Assume further that A has a greater population standard deviation than B. Which curve is taller, and why?
Curve B is taller because smaller standard deviations produce thinner curves.
What are the categorical variables in your survey?
Everything but average annual income and family size
True or False: All positive correlations indicate stronger relationships than all negative correlations.
False
True or False: An r of -1.0 proves a strong cause and effect relationship between x and y
False
True or False: If the population of interest is all day care centers in the United States, a sample of day care centers could be either all day care centers in New York City or a randomly selected group of day care centers throughout the US. Either sample is equally good.
False
Which of the following is true about the areas described under the normal curve?
Fewer than one percent of the cases are located three standard deviations above or below the mean.
A linear regression line indicates the amount of grams of the chemical CuSO4 (the response variable, y) that dissolve in water at various temperatures in Celsius (the explanatory variable, x). The least-squares regression line is y= 10.14+0.51x . Give the meaning of the slope of the regression line in the context of the problem.
For each one-degree rise in the temperature, you can dissolve 0.51 more grams of CuSO4.
Using the regression equation above, correctly interpret the slope
For every additional streetlight per block, the crimes per month decrease by 0.2.
Which of the following would not represent an instance of independent events when using the two specially created dice?
Getting a 9 on the first die AND getting a sum of 19 on the two die combined.
Which of the following are discrete random variables? I. The enrollment at state universities II. The outcomes of a loaded die III. The set of all random numbers between 1 and 10
I and II only
Which of the following are requirements of a discrete probability distribution? I. 0 ≤ p(x) ≤ 1 II. p(x) - 1 = 0 III. Σp(x) = 1
I and III
Which of the following examples would constitute a discrete random variable? I. Total number of points scored in a football game II. Height of the ocean's tide at a given location III. Number of near collisions of aircraft in a year
I and III
Which of the following are true? I. Two events are mutually exclusive if they can't both occur at the same time. II. Two events are independent if they have the same probability. III. An event and its complement have probabilities that always add to 1.
I and III only
Which of the following can stemplots show? I. Symmetry II. Gaps III. Clusters IV. Outliers
I, II, III, and IV
Which of the following can outliers affect significantly? I. Mean II. Median III. Standard deviation IV. Range V. Interquartile range
I, III, and IV
Which of the following are not essential characteristics of a binomial event? I. Each outcome must be independent. II. The sample size must be at least 20. III. A trial can have only two possible outcomes.
II only
Which of the following is a characteristic of a census?
It gathers data from every member of a population.
Histograms are most useful in displaying:
Large numeric data sets
Since the distribution of housing prices in a community is usually skewed right, which measure of center should you use for housing prices?
Median
The proper notation for a normal distribution with a mean of 250 and standard deviation of 25 is:
N(250, 25)
You believe that a normal probability plot of 30 data points provides evidence that the original data is normally distributed. If this is true, then the pattern of points on this normal probability plot is:
None of the above
When you have a normal distribution and you know that the area above a given value of x is 0.35, you also know that:
None of the above.
Number 112 (Omit)
Omit
Which of the variables you collect are continuous data?
Only average annual income
Which one of the following activities is not an example of data gathering?
Reaching a conclusion about the results of a reading program
Which table correctly shows the aggregation of the data?
Remissions Death Rate A 9 7 0.563 B 11 8 0.579
You randomly choose one attendee to speak with about his or her political views. Of the individuals listed below, this individual is most likely a(n):
Republican from Washington, DC
Which of the following is the best representative sample of the adult population in the United States?
Simple random sample of 1000 adults from across the country
What's the lurking variable when the data for early and advanced cancers are combined?
Stage of cancer (Early or Advanced)
Consider a survey in which 79% of the respondents said yes to the following question: Agree or disagree: Since our economy can't sustain itself without a healthy environment, it's important that Congress pass laws to protect the environment. What's a reasonable reaction to the survey results?
They're not valid, due to a leading question.
Consider the data set A: (2,8), (3,6), (4,9), and (5,9). Which of the following is the proper interpretation of the coefficient of determination?
Thirty percent of the variation in the y-values can be explained by variation of the x-values.
Which of these are categorical data?
The different types of anteaters
.Which measure of central tendency and measure of variation should be used with a normally distributed distribution?
The mean and standard deviation
Six radio listeners are surveyed. Their favorite FM stations are: 89.1, 89.1 89.1, 94.7, 94.7 and 104.3. Based on these data, you want to name the favorite station of a typical listener. You should name:
The mode, which is 89.1
All of the following statements are true about the normal distribution except:
The normal curve crosses the x-axis at z-scores above 3.0 and below -3.0.
If two events, A and B, are complementary, what else must be true?
They are mutually exclusive.
Let's say you're interested in the effects on boys of different dosage levels of a new drug for the treatment of ADD. You set up an experiment to consider the factor of dosage with two levels (300 mg vs. 500 mg). What would be the different treatment groups of the experiment within each block?
Three groups: placebo drug/300 mg of new drug/500 mg of new drug
Which treatment is actually more effective?
Treatment A
True or False: Blocking in an experiment and stratifying in a survey accomplish the same thing. They control the amount of variation in key characteristics within the total sample, such as race or gender, that are likely to be important to the outcome of interest.
True
True or False: In the survey of your neighbors described above, the only discrete quantitative data you're collecting about your neighbors is family size.
True
True or False: On the least-squares regression line, the point x y, always has a residual of 0
True
True or False: The number of home runs made by most National League teams were in the 90s; the number of home runs made by most teams overall were in the 80s.
True
A firm administers a survey in the state of New York. The survey is mailed out to a random set of 5,000 households throughout the state, and responses are received from 200 households. The two key questions on the survey are: 1) Whom do you plan to vote for in the upcoming Senate election? 2) Do you agree with the idea of imposing term limits on the amount of time a Senator can spend in office? What is a possible problem with this survey?
Voluntary response bias
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?
Voluntary response sample
Which of the following is true?
When success rates for early and advanced cancers are kept separate, Treatment A has a higher success rate. But when data for the two stages are combined, Treatment B has a higher rate.
For a semester project, a student needs to select a random sample of 10 students from his senior class of 250. He carefully numbers the class list from 000 to 249 and then uses a random number generator to obtain 3-digit random numbers. The 10 unique numbers are his sample. He notices that they all belong to the same AP Calculus class. Another student claims that this could not be a random sample. Which of the following is true?
Whether a sample is a random sample or not is determined by the sampling method, not the results. The method used here is valid.
Which of the following determines the sign of r?
Whether the value of y increases or decreases as the value of x increases
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 completely randomized design with a control group
Double-blind is best described as:
a design in which neither the experimenter nor the subject knows who is in the treatment group and who is in the control group
A block is best described as:
a group of subjects that are similar in some way known to affect the response to the treatment
An experiment is conducted in which a series of tests are performed on pairs of identical twins who were raised separately. A comparison of scores on each pair of twins is used for analysis. This is best described as:
a matched-pairs procedure
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andrew looks like a small ********
Which of the following indicates the value of (8 2)(.3)^2(.7)^6
binompdf(8,0.3,2)
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):
blocking variable
Suppose that all sample data points are on the same line with a positive slope. What would r be for this sample?
r would be +1.0
Which of the following would indicate the strongest relationship between two variables?
r^2= 0.23
The box plot below represents a distribution that is:
right skewed
Influential points and outliers:
should be examined carefully to determine if they're part of the data set.
What is the standard deviation of Z?
square root of 72
An observational study based on survey data concluded that individuals who took more vitamin C were able to recover from the flu faster. You want to replicate this study using an experimental approach. The treatment in this experiment might be:
the amount of vitamin C taken per day: 0 mg, 1000 mg, 2000 mg, or 3000 mg.
Number 86 (Exempt)
exempt
Number 87 (Exempt)
exempt
Number 90 (Exempt)
exempt
When looking at a scatterplot of two variables, the variable along the horizontal axis is typically referred to as the:
explanatory variable
Suppose the maximum number of hours of study among the students in your sample is 6. If you used the equation to predict the test score of a student who studied 8 hours a day, your prediction would be considered a (an):
extrapolation.
A normal probability plot:
graphs raw scores against z-scores of percentile ranks
The kind of sampling strategy least likely to produce statistics that are good estimates of population parameters is a:
haphazard sample
A residual:
is how much an observed y-value differs from a predicted y-value.
You've read a story in The New York Times claiming that individuals who engage in aerobic exercise for at least an hour a day demonstrate fewer symptoms of depression. You read that an experiment was conducted in which a researcher first administered a survey on depression and self-esteem to 100 individuals and then taught them some proper techniques of aerobic exercise. The 100 individuals were then sent off to exercise at least one hour a day. After two months, the depression and self-esteem survey was administered again and showed that depression symptoms declined and self-esteem increased. The experimental design used here is a:
matched pairs before and after design
The goal of the least-squares regression is to compute a line that:
minimizes the sum of the squared residuals.
For which of these values of n and p can you use the normal approximation to the binomial distribution?
n = 60, p = 0.4
Under what conditions can you use a normal distribution to approximate a binomial distribution?
np ≥ 10 and n (1 - p) ≥ 10
All of the following are examples of a sample that suffers from an undercoverage bias except:
the mean income of US citizens, based on Census data
Replication is best described as:
the policy of repeating an experiment on different subjects to reduce chance variation and to determine the generalizability of the findings.
All the following statements about the sample standard deviation are true, except:
the standard deviation is negative when there are extreme values in the sample
The placebo effect is best described as:
the tendency of subjects to respond favorably to any treatment.
An important reason a market researcher collects data using a stratified random sample rather than a simple random sample is:
to make a representative sample more likely than one produced by simple random sampling.
An outlier:
usually has a strong effect on the correlation coefficient and regression line and can also be an influential point.
In a normal distribution with a mean of 30 and a standard deviation of 5, you'd find the largest proportion of cases between:
x = 25 and x = 35
Use the sample data set {(8,4), (4,3), (7,3), and (5,2)}. 69. Calculate the least-squares regression line. A. y= 0.3+1.2x B. y= -0.02+0.9x C. y= 1.5+1.5x D. y= 4.8-3x E. y= 1.2+ 0.3x
y=1.2+.3x
In population H, what is the z-score, to the nearest tenth, associated with the height 65 inches?
z = -0.4
. For population W, find the z-score associated with a weight of 120 pounds
z = -1.6
Randomly selected students are asked whom they're going to vote for in the next student body election. The sample space is {Joan, Harvey, Anita, Luis}. Which of the following represents a legitimate assignment of probabilities for this sample space?
{0.1, 0.2, 0.3, 0.4}