Unit 1
Unit 2
Unit 3
Unit 4
Unit 5
100
A random sample of 374 United States pennies was collected, and the age of each penny was determined. According to the boxplot below, what is the approximate interquartile range (IQR) of the ages?
A
8
B
10
C
16
D
40
E
50
C - 16
100
A sample of 942 homeowners are classified, in the two-way frequency table below, by the number of credit cards they have and the number of years they have owned their current homes.
Of the homeowners in the sample who have four or more credit cards, what proportion have owned their current homes for at least one year?
A sample of 942 homeowners are classified, in the two-way frequency table below, by the number of credit cards they have and the number of years they have owned their current homes.
Of the homeowners in the sample who have four or more credit cards, what proportion have owned their current homes for at least one year?
A: 78/212
B: 78/258
C: 78/942
D: 212/942
E: 258/942
A: 78/212
100
A florist wanted to investigate whether a new powder added to the water of cut flowers helps to keep the flowers fresh longer than just water alone. For a shipment of roses that was delivered to the store, the florist flipped a coin before placing each rose in its own individual container with water. If the coin landed heads up, the rose was placed in water with the new powder; otherwise, the rose was placed in water alone. Which of the following is the best description of the method used by the florist?
A: A census, because all roses are assigned to a container
B: An experiment with a completely randomized design
C: An experiment with a blocked design, with blocking by type of water
D: An experiment with a matched-pairs design
E: An observational study
B: An experiment with a completely randomized design
100
Ten percent of all Dynamite Mints candies are orange and 45 percent of all Holiday Mints candies are orange. Two independent random samples, each of size 25, are selected - one from Dynamite Mints candies and the other from Holiday Mints candies. The total number of orange candies in the two samples is observed. What are the expected total number of orange candies and the standard deviation for the total number of orange candies, respectively, in the two samples?
A: 7 and 2.905
B: 7 and 3.987
C: 13.75 and 2.233
D: 13.75 and 2.905
E: 13.75 and 3.987
D: 13.75 and 2.905
100
Which of the following pairs of sample size n and population proportion p would produce the greatest standard deviation for the sampling distribution of a sample proportion p̂?Responses
A: n = 1,000 and p close to 0
B: n = 1,000 and p close to 1
C: n = 1,000 and p close to 1/2
D: n = 100 and p close to 0
E: n = 100 and p close to 1/2
E: n = 100 and p close to 1/2
200
Which of the following statements must be true about the data sets A and B displayed in the histograms above?
A: The mean of data set A is equal to the mean of data set B.
B: The median of data set A is equal to the median of data set B.
C: The range of data set A is equal to the range of data set B.
D: The standard deviation of data set A is less than the standard deviation of data set B.
E: The standard deviation of data set A is greater than the standard deviation of data set B.
E: The standard deviation of data set A is greater than the standard deviation of data set B.
200
The following segmented bar chart shows the number of flights that were either on time or delayed at three different airports on one day.
Which of the following statements is supported by the bar chart?
A: Airport T has the greatest percentage of on-time flights compared to the other two airports.
B: Airport R has the least percentage of on-time flights compared to the other two airports.
C: The number of on-time flights at Airport S is half the number of on-time flights at Airport T.
D: The number of on-time flights at Airport R is less than the number of on-time flights at Airport S.
E: The number of flights at Airport T is equal to the total number of flights at Airports R and S combined.
C: The number of on-time flights at Airport S is half the number of on-time flights at Airport T.
200
The director of a fitness center wants to examine the effects of two exercise classes (spinning and aerobics) on body fat percentage. A six-week spinning class and a six-week aerobics class are offered at the same time and on the same days, so that a person can enroll in only one of them. A new class of each is about to begin, and each class has 25 people in it. Ten people are randomly selected from each class. Each person's body fat percentage is measured at the beginning and again at the end of the six-week class. Using the change in body fat percentage as the response variable and conducting a test at the a = 0.01 level, the director determines that there is a significant difference between the treatment means. Which of the following is a confounding variable in the study?
A: The director's choice of spinning and aerobics classes as the types for use in the study.
B: The random sample of 10 people from each class.
C: The participants' choice of which class to take.
D: The use of body fat percentage as the measure of effectiveness of the treatment.
E: The fact that both classes were conducted three times each week at the same time of day and for the same amount of time each day.
C: The participants' choice of which class to take.
200
A player pays $15 to play a game in which a chip is randomly selected from a bag of chips. The bag contains 10 red chips, 4 blue chips, and 6 yellow chips. The player wins $5 if a red chip is selected, $10 if a blue chip is selected, and $20 if a yellow chip is selected. Let the random variable represent the amount won from the selection of the chip, and let the random variable represent the total amount won, where . What is the mean of ?
A: $10.50
B: $4.50
C: -$4.50
D: -$6.50
E: -$10.50
C: -$4.50
200
There were 5,317 previously owned homes sold in a western city in the year 2000. The distribution of the sales prices of these homes was strongly right-skewed, with a mean of $206,274 and a standard deviation of $37,881. If all possible simple random samples of size 100 are drawn from this population and the mean is computed for each of these samples, which of the following describes the sampling distribution of the sample mean?
A: Approximately normal with mean $206,274 and standard deviation $3,788
B: Approximately normal with mean $206,274 and standard deviation $37,881
C: Approximately normal with mean $206,274 and standard deviation $520
D: Strongly right-skewed with mean $206,274 and standard deviation $3,788
E: Strongly right-skewed with mean $206,274 and standard deviation $37,881
A: Approximately normal with mean $206,274 and standard deviation $3,788
300
Suppose a new regulation requires businesses to pay all employees a minimum wage of per hour. A small coffee shop currently has employees— employees whose wages are less than per hour and employees whose wages are more than per hour. To meet the new regulation, the coffee shop plans to increase the wages of the employees whose wages are less than per hour to per hour. The other employees will not receive a wage increase at this time.
Which of the following must be true about the median wage of the employees after the wage increase occurs?
A: The median wage will be greater than per hour.
B: The median wage will increase but will be less than per hour.
C: The median wage will be per hour.
D: The median wage will not change.
E: The median wage cannot be determined from the information provided.
C: The median wage will be per hour.
300
A survey of 57 students was conducted to determine whether or not they held jobs outside of school. The two-way table above shows the number of students by employment status (job, no job), and class (juniors, seniors). Which of the following best describes the relationship between employment status and class?
A: There appears to be no association, since the same number of juniors and seniors have jobs.
B: There appears to be no association, since close to half of the students have jobs.
C: There appears to be an association, since there are more seniors than juniors in the survey.
D: There appears to be an association, since the proportion of juniors having jobs is much larger than the proportion of seniors having jobs.
E: A measure of association cannot be determined from these data.
D: There appears to be an association, since the proportion of juniors having jobs is much larger than the proportion of seniors having jobs.
300
An experiment was conducted to assess the effect of baking temperature on the density of bread. A large batch of white bread dough and a large batch of whole wheat bread dough were prepared. Each of the batches was formed into loaves, resulting in a total of loaves. Each of the white bread loaves was randomly assigned to one of three baking temperatures (low, medium, and high), so that loaves were baked at the low temperature, were baked at the medium temperature, and were baked at the high temperature. A similar process of random assignment was carried out for the whole wheat bread loaves.
Which of the following are the treatments in the experiment?
A: The loaves of bread
B: The type of bread (white, whole wheat)=
C: The density of the bread
D: The baking temperatures (low, medium, high)
E: The two batches of bread dough
D: The baking temperatures (low, medium, high)
300
A middle school chess club has 5 members: Adam, Bradley, Carol, Dave, and Ella. Two students from the club will be selected at random to participate in the county chess tournament. What is the probability that Adam and Ella will be selected?
ResponsesA: 1/20
B: 1/10
C: 1/8
D: 1/7
E: 1/4
B: 1/10
300
For which of the following conditions is it not appropriate to assume that the sampling distribution of the sample mean is approximately normal?
A: A random sample of 8 taken from a normally distributed population
B: A random sample of 50 taken from a normally distributed population
C: A random sample of 10 taken from a population distribution that is skewed to the right
D: A random sample of 75 taken from a population distribution that is skewed to the left
E: A random sample of 100 taken from a population that is uniform
C: A random sample of 10 taken from a population distribution that is skewed to the right
400
The boxplots above summarize two data sets, A and B. Which of the following must be true?
Set A contains more data than Set B.
The box of Set A contains more data than the box of Set B.
The data in Set A have a larger range than the data in Set B.
3 only
400
A botanist found a correlation between the length of an aspen leaf and its surface area to be 0.94. Why does the correlation value of 0.94 not necessarily indicate that a linear model is the most appropriate model for the relationship between length of an aspen leaf and its surface area?
A: The value must be exactly 1 or to indicate a linear model is the most appropriate model.
B: The value must be 0 to indicate a linear model is the most appropriate model.
C: A causal relationship should be established first before determining the most appropriate model.
D: The value of 0.94 implies that only 88% of the data have a linear relationship.
E: Even with a correlation value of 0.94, it is possible that the relationship could still be better represented by a nonlinear model.
E: Even with a correlation value of 0.94, it is possible that the relationship could still be better represented by a nonlinear model.
400
Which of the following is a benefit to using a random sample for an observational study?
A: The random sample allows for different treatments to be assigned.
B: A causal relationship can be determined.
C: The results of the observational study can be generalized to the population.
D: A random sample is the easiest method of data collection.
E: The distribution of the sample will match the distribution of the population.
C: The results of the observational study can be generalized to the population.
400
Each person in a group of twenty people at a hotel orders one meal chosen from oatmeal, eggs, or pancakes and one hot beverage chosen from coffee or tea. One person will be selected at random from the twenty people. What is the sample space for the meal and beverage for the person selected?
A: {(oatmeal, coffee), (oatmeal, tea), (eggs, coffee), (eggs, tea), (pancakes, coffee), (pancakes, tea)}
B: {(oatmeal, pancakes), (oatmeal, eggs), (eggs, pancakes), (coffee, tea)}
C: {(coffee, tea, oatmeal), (coffee, tea, eggs), (coffee, tea, pancakes)}
D: {oatmeal, coffee, pancakes, eggs, tea}
E: {(oatmeal, eggs, pancakes), (coffee, tea)}
A: {(oatmeal, coffee), (oatmeal, tea), (eggs, coffee), (eggs, tea), (pancakes, coffee), (pancakes, tea)}
400
Researchers working for a certain airline are investigating the weight of carry-on bags. The researchers will use the mean weight of a random sample of 800 carry-on bags to estimate the mean weight of all carry-on bags for the airline.
Which of the following best describes the effect on the bias and the variance of the estimator if the researchers increase the sample size to 1,300?
A: The bias will decrease and the variance will remain the same.
B: The bias will increase and the variance will remain the same.
C: The bias will remain the same and the variance will decrease.
D: The bias will remain the same and the variance will increase.
E: The bias will decrease and the variance will decrease.
C: The bias will remain the same and the variance will decrease.
500
A graph (not shown) of the selling prices of homes in a certain city for the month of April reveals that the distribution is skewed to the left. Which of the following statements is the most reasonable conclusion about the selling prices based on the graph?
A: The mean is greater than the median.
B: The median is the average of the first quartile and the third quartile.
C: There are fewer selling prices between the first quartile and the median than there are between the median and the third quartile.
D: There are more selling prices that are less than the mean than selling prices that are greater than the mean.
E: The value of maximum minus third quartile is less than the value of first quartile minus minimum.
E: The value of maximum minus third quartile is less than the value of first quartile minus minimum.
500
Which of the following is the best description of a positive association between two variables?
A: The values will create a line when graphed on a scatterplot.
B: The values will create a line with positive slope when graphed on a scatterplot.
C: As the value of one of the variables increases, the value of the other variable tends to decrease.
D: As the value of one of the variables increases, the value of the other variable tends to increase.
E: All values of both variables are positive.
D: As the value of one of the variables increases, the value of the other variable tends to increase.
500
A large simple random sample of people aged nineteen to thirty living in the state of Colorado was surveyed to determine which of two MP3 players just developed by a new company was preferred. To which of the following populations can the results of this survey be safely generalized?
A: Only people aged nineteen to thirty living in the state of Colorado who were in this survey
B: Only people aged nineteen to thirty living in the state of Colorado
C: All people living in the state of Colorado
D: Only people aged nineteen to thirty living in the United States
E: All people living in the United States
B: Only people aged nineteen to thirty living in the state of Colorado
500
A box contains 10 tags, numbered 1 through 10, with a different number on each tag. A second box contains 8 tags, numbered 20 through 27, with a different number on each tag. One tag is drawn at random from each box. What is the expected value of the sum of the numbers on the two selected tags?
A: 13.5
B:14.5
C: 15.0
D: 27.0
E: 29.0
E: 29.0
500
A manufacturer of cell phone batteries claims that the average number of recharge cycles for its batteries is 400. A consumer group will obtain a random sample of 100 of the manufacturer’s batteries and will calculate the mean number of recharge cycles.
Which of the following statements is justified by the central limit theorem?
A: The distribution of the number of recharge cycles for the sample is approximately normal because the population mean of 400 is greater than 30.
B: The distribution of the number of recharge cycles for the sample is approximately normal because the sample size of 100 is greater than 30.
C: The distribution of the number of recharge cycles for the population is approximately normal because the sample size of 100 is greater than 30.
D: The distribution of the sample means of the number of recharge cycles is approximately normal because the sample size of 100 is greater than 30.
E: The distribution of the sample means of the number of recharge cycles is approximately normal because the population mean of 400 is greater than 30.
D: The distribution of the sample means of the number of recharge cycles is approximately normal because the sample size of 100 is greater than 30.