Stat Attack 2

The stem-and-leaf plot shows science test scores for Mr. Park's class. What is the median score?

Key: 6 | 2 = 62

1. 82.5
2. 83.5
3. 78
4. 85

The histogram shows the number of books read per month by 30 students. What percent of students read 6 or more books per month?

1. 20%
2. About 33%
3. 50%
4. About 67%

The box-and-whisker plot below shows daily high temperatures (in °F) for one month in Atlanta. What is the IQR?

1. 20
2. 35
3. 50
4. 65

Two soccer teams' goals scored per game are graphed on the dot plot below. Team Astro is shown with circles (●) and Team Blaze with X marks. Which observation is correct?

1. The medians are 3 goals apart, with Blaze higher.
2. The medians are 1 goal apart, with Blaze higher.
3. Astro has the higher median.
4. Both teams have the same mode.

A track runner recorded her 400 m times (in seconds) over 7 practices: 60, 62, 64, 65, 66, 68, 70. What is the mean time?

1. 64
2. 64.5
3. 65
4. 66

A factory produces 5,000 phone cases each day. To check for defects, the quality inspector randomly examines 50 cases from the day's batch. Fill in the blanks:

The principal wants to know what after-school activities students are most interested in. She needs a sample of 40 students. Which methods produce a random sample?

1. Survey 40 students from the chess club.
2. Number every student and use a random number generator to select 40 IDs.
3. Pull 40 names from a hat that contains every student's name.
4. Ask the first 40 students who walk into the cafeteria for lunch.
5. Survey 40 students wearing tennis shoes that day.
6. Survey the 40 students who attend Friday's school dance.

Tom wants to know which app teens use most. He surveys 25 people leaving the mall on Saturday afternoon. Which statements are TRUE?

1. The sample is a random sample.
2. The sample is biased toward people who shop at the mall.
3. The sample excludes teens who don't go to the mall.
4. The sample represents all teens in the area.
5. The sample is NOT a random sample.
6. The sample includes the entire teen population.

Two surveys ask the same question to predict an election outcome. Survey A polls 30 random voters. Survey B polls 300 random voters. Which is more likely to give a reliable estimate of the actual outcome?

1. Survey A, because smaller samples are easier to manage.
2. Survey B, because larger random samples reduce the chance of unusual results.
3. They are equally reliable since both are random.
4. Neither — only a census can be reliable.

In a poll of 200 voters, 130 said they support a new park proposal. If the town has 5,000 voters total, about how many would you predict support the proposal?

1. 1,300
2. 2,600
3. 3,250
4. 4,000

The stem-and-leaf plot shows the number of minutes students spent on homework last night. How many students spent at least 30 minutes on homework?

Key: 1 | 2 = 12 minutes

1. 5
2. 7
3. 8
4. 11

Mr. Lee's daily phone-screen times (in minutes) for one week were: 45, 60, 38, 72, 55, 48, 62. What is the IQR of his data?

1. 14
2. 17
3. 22
4. 34

The histogram shows the movies watched per month by students. Which interval contains the fewest students?

1. 0–1 movies
2. 2–3 movies
3. 6–7 movies
4. 8+ movies

A class recorded the number of pets per household. The dot plot of their results is shown below. How would you best describe the shape of this distribution?

1. Symmetric — mirrored on both sides of the center.
2. Skewed right — most data on the left with a tail trailing right.
3. Skewed left — most data on the right with a tail trailing left.
4. Uniform — every value occurs about equally often.

A coach recorded the number of laps each runner finished in 10 minutes: 6, 7, 7, 8, 8, 9, 9, 10, 24. Which value is the outlier, and what would happen if you removed it?

1. 6 is the outlier; the mean would increase if removed.
2. 10 is the outlier; the median would change a lot.
3. 24 is the outlier; the mean would decrease and the median would barely change.
4. There is no outlier — the data is normal.

Two PE classes recorded the number of sit-ups done in one minute. The box plots are shown below. Which statement is TRUE?

1. Class A has a higher median than Class B.
2. Both classes have the same range.
3. Class B has a larger IQR than Class A.
4. Class A has a larger spread overall than Class B.

Which stem-and-leaf plot correctly represents this data set? 23, 28, 31, 34, 39, 42, 45, 47

A real estate agent lists the sale prices of 6 homes on one street: $200K, $210K, $215K, $220K, $230K, and $1,500K (a celebrity's mansion). Which measure better represents a typical home price on this street, and why?

1. The mean, because it uses every data point.
2. The median, because it isn't pulled up by the unusually high price.
3. The mode, because it appears most often.
4. The range, because it shows the full spread.

Maria flipped a coin 50 times as part of a probability simulation. The coin landed on heads 28 times. What is the experimental probability that the coin lands on heads?

1. 50%
2. 56%
3. 28%
4. 44%

A national pet food company surveys 50 dogs at a single dog park in Denver about which flavor they prefer. The company plans to use the results to decide what flavors to sell in stores nationwide. What is the population for this study?

1. The 50 dogs surveyed at the dog park.
2. All dogs in the United States.
3. All dogs that visit dog parks in Denver.
4. Dog owners who shop at pet food stores.