Making Inferences of Data

Pizza Hut surveyed a random sample of students to determine what pizza they prefer. Cheese pizza was preferred by 40 students. Pepperoni pizza was preferred by 28 students. Based on the results, how many of the 340 students in the 9th grade can be expected to prefer cheese pizza?

A random sample from the 6th and 7th grade student population was taken to determine which clubs were the most popular.

What percent of 6th graders are involved in the yearbook club?

Data is collected from a random sample of 40 people at the public library.  If the public library has 300 patrons, then which of the following conclusions can be drawn?

• Exactly 42% of the library patrons chose a mystery.

• Non-fiction and science fiction represent over half of the selections.

• Over 25% of the library patrons chose a science fiction book.

• 136 total patrons can be expected to choose a non-fiction book.

A grocery store polls every twentieth customer to determine if they are satisfied with the cleanliness of the store.  Forty customers are surveyed, and 26 are satisfied.  What conclusion can be drawn for the 800 daily customers?

• 65% of the customers are unsatisfied with the cleanliness of the store.

• Of the 800 customers, 520 would be satisfied with the cleanliness of the store.

• 40% of the customers are satisfied with the cleanliness of the store.

• 25% of the customers are not satisfied with the cleanliness of the store.

The faculty of BMS were asked to state their age. The results are shown above in the box plot. What is the minimum age found in the box plot?

• 23

• 33

• 42

• 20

Students record the number of minutes they read at home.  The box plot shows the summary of the results.  Which statement best describes the data? 

• A quarter of the students read for 30-40 minutes.

• The interquartile range is 30.

• About half the students read for 50 minutes or more.

• The average number of minutes read was 47.

What is the interquartile range (IQR)?

• 4

• 64

• 60

• 8

Based on the box plot, which statement is NOT true?

• The oldest team member is 24.

• The median age is 22.

• Fifty percent of the participants are older than 22.

• Less than 25% of the participants are 20 or younger.

The box plot below shows the number of siblings in Mrs. Hines’ class. Which of the following statements is not true?

• The interquartile range of the data is approximately 2.

• The median number of siblings in Mrs. Hines' class is approximately 1.75.

• There is at least one student who has no siblings.

• Over half of the students in Mrs. Hines' class have two or more siblings.

The dot plot below represents the number of dollars in allowance that students receive each week in Mrs. Jimenez's class. Which of the following statements is the best descriptions for the data?

• The data is spread out and skewed left.

• Most of the data is far from the median and is skewed right.

• The data is symmetrical and close to the median.

• The data is spread out with $5 being the most common weekly allowance.