Data & statistics: Algebra 1 Regents Practice
Practice Data & statistics for the Algebra 1 Regents with real-style questions and full worked solutions. Miss one? Read the solution — the exam reuses the same ideas every year.
A ball is launched upward and its height (feet) is recorded each second: at $0$ s, $11$; at $1$ s, $59$; at $2$ s, $75$; at $3$ s, $59$; at $4$ s, $11$. Based on these data, which statement is a valid conclusion?
- (A) The ball reaches a maximum height of $11$ feet.
- (B) The ball reaches its greatest height at $2$ seconds. ✓
- (C) The ball lands on the ground at $4$ seconds.
- (D) The ball was launched from a height of $0$ feet.
Worked solution
Read the table for what it actually says: the largest height (75 ft) occurs at t = 2 s, and the launch height is the value at t = 0 (11 ft).
What is the median of the data set $\{4,\ 7,\ 9,\ 12,\ 18\}$ ?
- (A) $9$ ✓
- (B) $10$
- (C) $12$
- (D) $7$
Worked solution
The median is the middle value of an ordered list (average the two middles if the count is even).
For the data set $3,\ 5,\ 7,\ 8,\ 10,\ 12,\ 14,\ 16$, what is the interquartile range (IQR)?
- (A) $9$
- (B) $19$
- (C) $7$ ✓
- (D) $13$
Worked solution
The interquartile range measures the spread of the middle 50% of the data and equals $Q_3-Q_1$.
Four scatter plots have the correlation coefficients listed below. Which value indicates the strongest linear relationship?
- (A) $0.88$
- (B) $-0.09$
- (C) $0.42$
- (D) $-0.90$ ✓
Worked solution
The closer $|r|$ is to $1$, the stronger the linear relationship; the sign shows direction only, not strength.
A box plot of winter snowfall has a lower quartile of $Q_1 = 30$ inches and an upper quartile of $Q_3 = 80$ inches. What is the interquartile range (IQR)?
- (A) $110$
- (B) $30$
- (C) $50$ ✓
- (D) $80$
Worked solution
The interquartile range is the width of the middle 50% of the data: upper quartile minus lower quartile.
Of 100 students surveyed, 44 are seniors. Of the 65 who prefer videos, 42 are juniors. Determine how many seniors prefer music.
Worked solution
Fill the two-way table: subtract junior video-watchers from the video total to get senior video-watchers, then subtract from all seniors.
A tutor models the relationship between hours studied, $x$, and a student's test score, $y$, with the line of best fit $y=2.5x+60$. Which statement best interprets the slope of this line?
- (A) For each additional point scored, study time increases by $2.5$ hours.
- (B) For each additional hour studied, the predicted test score increases by $2.5$ points. ✓
- (C) A student who does not study is predicted to score $2.5$ points.
- (D) For each additional hour studied, the predicted test score increases by $60$ points.
Worked solution
The slope of a regression line is the unit rate of change of the response variable $y$ for each one-unit increase in the explanatory variable $x$.
The two-way frequency table shows the pet preferences of 80 students. | | Dog | Cat | Total | |---|---|---|---| | Male | 26 | 24 | 50 | | Female | 9 | 21 | 30 | | Total | 35 | 45 | 80 | According to the table, what percent of the female students prefer cats?
- (A) $\approx 46.7\%$
- (B) $30\%$
- (C) $26.25\%$
- (D) $70\%$ ✓
Worked solution
A conditional relative frequency divides by the row (or column) total of the given group, here the $30$ female students.
What is the mean of the data set $10, 12, 14, 16, 48$?
- (A) $38$
- (B) $20$ ✓
- (C) $13$
- (D) $14$
Worked solution
The mean is the sum of all values divided by how many there are. The total $100$ divided by $5$ gives $20$. (The median is $14$ and the range is $38$, which are different measures.)
Consider the data set $2, 4, 6, 8, 10$. Suppose the value $10$ is changed to $100$. Explain what happens to the mean and to the median of the data set. Support your answer with calculations.
Worked solution
The mean uses the actual value of every data point, so a single large value (an outlier) raises it substantially, here from 6 to 24. The median depends only on position, and since the middle value is still 6, the median is resistant to the change.
Four sets of data were each fit with a line of best fit. Which value of the correlation coefficient $r$ indicates the strongest linear relationship?
- (A) $r = 0.87$
- (B) $r = -0.95$ ✓
- (C) $r = -0.12$
- (D) $r = 0.34$
Worked solution
The strength of a linear relationship is measured by how close $|r|$ is to 1, regardless of sign. Since $|-0.95| = 0.95$ is the largest absolute value, it represents the strongest relationship. The negative sign only tells us the line has a negative slope.
Emma's scores on five quizzes were $70, 75, 80, 85,$ and $100$. Which statement about this data set is true?
- (A) The median is greater than the mean.
- (B) The mean and the median are equal.
- (C) The mean is greater than the median. ✓
- (D) The median of the data set is $82$.
Worked solution
The mean of the five scores is 82 and the median, the middle value, is 80. Because the high score of 100 pulls the data to the right, the mean exceeds the median, which is typical of a distribution skewed toward larger values. The value 82 is the mean, not the median.
The number of goals scored by a soccer team in six games was $2, 4, 4, 6, 9,$ and $11$. Which statement about this data set is true?
- (A) The mean is $6$ and the median is $4$.
- (B) The mean is $6$ and the median is $6$.
- (C) The mean is $6$ and the median is $5$. ✓
- (D) The mean is $5$ and the median is $6$.
Worked solution
The mean is the sum $36$ divided by $6$ values, which is $6$. Since there is an even number of data values, the median is the average of the two middle values, $4$ and $6$, giving $5$. Choosing just the value $4$ or $6$ as the median is a frequent error with even-sized data sets.
A study compared the number of hours students spent watching television each week and their scores on a math test. The correlation coefficient for the data was $r = -0.9$. Which statement best describes the relationship between the two variables?
- (A) There is a weak negative linear relationship.
- (B) There is a strong positive linear relationship.
- (C) There is no linear relationship.
- (D) There is a strong negative linear relationship. ✓
Worked solution
The strength of a linear relationship is measured by how close $|r|$ is to 1, and the sign of $r$ gives the direction. Since $r = -0.9$ is close to $-1$, the data show a strong negative linear relationship: more television hours are associated with lower test scores.
The number of books read last year by each of nine students is listed below: $3,\ 5,\ 5,\ 6,\ 7,\ 8,\ 8,\ 8,\ 10$. Determine the median and the interquartile range of this data set. Show how you arrived at each value.
Worked solution
With nine ordered values, the median is the fifth value, 7. The first quartile is the median of the four values below the median and the third quartile is the median of the four values above it, giving $Q_1=5$ and $Q_3=8$, so the interquartile range is $8-5=3$.
The number of books read last month by each of seven students is listed below. $$4, \ 6, \ 6, \ 7, \ 9, \ 10, \ 14$$ Which statement about these data is true?
- (A) The median is greater than the mean.
- (B) The mean is equal to the median.
- (C) The mode is greater than the mean.
- (D) The mean is greater than the median. ✓
Worked solution
The mean of the seven values is $56/7 = 8$, the median is the middle value 7, and the mode is 6. Since $8 > 7$, the mean exceeds the median, which is typical for data skewed to the right by the large value 14.
A student computes the correlation coefficient for a set of bivariate data and gets $r = -0.92$. Which statement best describes the relationship between the two variables?
- (A) An increase in one variable causes a decrease in the other variable.
- (B) There is a strong negative linear relationship between the variables. ✓
- (C) There is a strong positive linear relationship between the variables.
- (D) There is a weak negative linear relationship between the variables.
Worked solution
The sign of $r$ gives the direction of the linear relationship and its absolute value gives the strength. Since $-0.92$ is negative and close to $-1$, the data show a strong negative linear relationship. The causation choice is wrong because correlation alone never establishes that one variable causes changes in the other.
A film's box-office earnings (millions of dollars) over its first six weeks are: $185,\ 150,\ 90,\ 50,\ 25,\ 5$ (weeks $1$ through $6$). Write the linear regression equation (round values to the nearest hundredth), state the correlation coefficient to the nearest hundredth, and describe the fit.
Worked solution
Enter the data, run linear regression for the equation and r, then judge strength by how close $|r|$ is to 1. A negative slope and r near −1 is a strong negative fit.
Andrea's quiz scores are $82,\,87,\,90,\,84$ and Joe's are $91,\,78,\,94,\,67$. Which statement is correct?
- (A) Both Andrea's mean and standard deviation are higher.
- (B) Both Joe's mean and standard deviation are higher.
- (C) Andrea's mean is higher, but Joe's standard deviation is higher. ✓
- (D) Joe's mean is higher, but Andrea's standard deviation is higher.
Worked solution
Compare means by averaging; standard deviation grows with spread, and Joe's scores vary far more widely.
The line of best fit for a data set is $y=3x+2$. For the observed data point $(4,\ 15)$, what is the residual?
- (A) $1$ ✓
- (B) $3$
- (C) $14$
- (D) $-1$
Worked solution
A residual is the observed value minus the predicted value; a positive residual means the point lies above the line of best fit.
Two data sets each have five values and a mean of $50$. Set A is $\{50,\ 50,\ 50,\ 50,\ 50\}$ and Set B is $\{30,\ 40,\ 50,\ 60,\ 70\}$. Which statement correctly compares their standard deviations?
- (A) Set A has the greater standard deviation because all of its values are equal.
- (B) The two sets have equal standard deviations because they have the same mean.
- (C) The standard deviations cannot be compared without more information.
- (D) Set B has the greater standard deviation because its values are more spread out from the mean. ✓
Worked solution
Standard deviation reflects how far data values fall from the mean; more spread means a larger standard deviation, regardless of the mean's value.
More Algebra 1 topics
- Systems of equations
- Exponential growth
- Solving linear equations
- Factoring quadratics
- Slope & rate of change