A city inspects all 4,300 restaurants and reports that 12% failed inspection. In this report, what are the 4,300 restaurants and the 12%?

A survey records each student's commute time in minutes, transportation mode, lunch period, and after-school club. Which recorded variable is quantitative?

A random sample of 80 seniors has a mean backpack mass of 6.2 kg. What is the 6.2 kg value?

A school analyst compares attendance records and final exam scores for current students without assigning attendance levels. What kind of study is this?

A registrar chooses 120 student IDs at random from 2,400 students to estimate the average number of credits earned. What are the 120 chosen IDs?

Use the histogram of delivery times. How many deliveries took at least 20 minutes but under 40 minutes?

Use the box plot of bus wait times. What is the median wait time?

Use the dot plot of goals scored per match. What is the mode?

Use the stem-and-leaf plot of practice times. How many times were at least 40 minutes?

Use the histogram of plant heights. What shape best describes the distribution?

Five soil samples have masses 3 kg, 5 kg, 6 kg, 8 kg, and 13 kg. What is the mean mass?

The six reaction times in seconds are 12, 15, 18, 20, 25, and 30. What is the median?

The ordered quiz scores are 14, 16, 18, 21, 22, 27, 29, 31, and 36. What is the interquartile range?

The wait times, in minutes, are 5, 6, 6, 7, 8, 9, and 35. Which measure of center is most pulled upward by 35?

The four leaf lengths in centimeters are 2, 4, 4, and 6. What is the sample standard deviation, rounded to the nearest hundredth?

Batteries last normally with $\mu =170$ hours and $\sigma =8$ hours. What is the z-score for 186 hours?

A normal model has $\mu =50$ and $\sigma =12$ for quiz scores. What raw score has $z=-1.5$?

Lengths of bolts are normal with mean 20 cm and standard deviation 3 cm. By the empirical rule, about what percent lie between 17 cm and 23 cm?

Exam scores are normal with $\mu =100$ and $\sigma =15$. A standard normal table gives $P(Z<2.00)=0.977$. About what percent score below 130?

The normal curve shades the region from $z=-1$ to $z=1$. By the empirical rule, about what percent is shaded?

Use the scatterplot of study hours and quiz scores. What association is shown?

A regression predicting water used, in liters, from shower length x minutes is $\hat{y}=2.5+0.8x$. A 10-minute shower used 12.0 liters. What is the residual?

For plants, height in cm after x weeks is predicted by $\hat{y}=12+3.4x$. What does the slope 3.4 mean?

For daily temperature and soup sales, a linear model has $r=-0.80$ and $r^2=0.64$. What does $r^2$ say?

Use the residual plot for a proposed linear model. What does the pattern suggest?

A counselor has a list of all 900 students and needs a sample of 60. What plan gives a simple random sample?

A district wants 100 survey responses representative of grades 9-12. It randomly selects 25 students from each grade. What sampling method is this?

In an experiment, 200 students are randomly assigned to use either a planning app or a paper planner for four weeks; completed assignments are counted. What is the treatment?

Researchers group patients by age under 40 and 40 or older, then randomly assign treatment within each group. Why use the age groups?

A newspaper asks readers to click a website poll about school start times. What bias is most likely?

Use the two-way table of permit test results. Among robotics students, what proportion passed? Give a decimal to two places.

A bag has 4 green and 6 yellow tiles. Two tiles are drawn without replacement. What is the probability both are yellow, as a fraction in lowest terms?

Rain has probability 0.30, and a bus being late has probability 0.20. If the events are independent, what is the probability both happen?

A factory item has defect probability 0.030. What is the probability a randomly chosen item is not defective? Give a decimal to three places.

At a school, P(soccer) = 0.35, P(band) = 0.25, and P(both) = 0.10. What is P(soccer or band)?

A library records late books returned by a student. The values 0, 1, 2, and 3 have probabilities 0.20, 0.50, 0.20, and 0.10. What is the expected value?

Each seed sprouts independently with probability 0.40. For 5 seeds, what is the probability exactly 2 sprout? Round to three decimals.

A student draws 4 cards without replacement from a 52-card deck and counts aces. Which binomial condition fails?

A free-throw shooter makes each shot with probability 0.25 independently. What is the expected number of shots until the first make?

A random variable takes values 1, 3, and 5 with probabilities 0.25, 0.50, and 0.25. What is its standard deviation, rounded to the nearest hundredth?

A population of cereal box masses has $\mu =500$ g and $\sigma =12$ g. For random samples of $n=36$, what is the standard deviation of $\bar{x}$?

A bottle-filling population has mean 150 mL and standard deviation 20 mL. For samples of 25 bottles, what is the mean of the sampling distribution of $\bar{x}$?

In a population, $p=0.40$. For random samples of $n=100$, what is the standard deviation of $\hat{p}$? Round to three decimals.

A population of daily step counts is strongly skewed. Random samples of 50 adults are taken. What is the approximate shape of the sampling distribution of $\bar{x}$?

For a sample proportion with $n=200$ and $p=0.08$, are Normal calculations reasonable by the success-failure condition?

A 95% confidence interval for mean commute time is 42.1 to 47.9 minutes. What are the point estimate and margin of error?

A random sample of 25 backpacks has $\bar{x}=18.4$ kg and $s=5.0$ kg. For a 95% t interval, $t^{\ast }=2.064$. What interval for $\mu$ is rounded to one decimal?

A poll of 400 voters has $\hat{p}=0.62$. Using $z^{\ast }=1.96$, what 95% confidence interval for p is rounded to three decimals?

A 90% confidence interval for mean student commute time is 21 to 27 minutes. What is the correct interpretation?

Keeping the same confidence level and sample proportion, what happens to a one-proportion confidence interval when the sample size increases?

A school tests whether mean refillable bottle mass is less than 500 g. Which hypotheses match this claim?

A test of $H_0:\mu =10$ against $H_a:\mu >10$ gives p = 0.032 at $\alpha =0.05$. What decision is correct?

A test of $H_0:\mu =50$ gives p = 0.04. What does p = 0.04 mean?

For a new filter, $H_0$ says the mean lead level equals the old filter's level, and $H_a$ says it is lower. What is a Type I error?

Use the calculator output for $H_0:\mu =30$ versus $H_a:\mu >30$. At $\alpha =0.05$, what decision is supported?

Two independent random samples of 200 customers each find 130 and 110 satisfied. What is ${\hat{p}}_1-{\hat{p}}_2$, first minus second?

Two independent samples compare mean plant growth: A has n=36, x-bar=82 cm, s=10; B has n=36, x-bar=78 cm, s=8. With t*=2.0, what 95% interval estimates ${\mu }_A-{\mu }_B$?

Use the lunch-choice table. Under independence, what is the expected count for grade 9 and salad?

A chi-square test of independence for club membership and bus use gives p = 0.18 at $\alpha =0.05$. What conclusion is justified?

A chi-square test of independence uses a table with 3 rows and 4 columns. What are the degrees of freedom?