Khan Academy | Practice: Valid Claims

The Read and Feed restaurant wants to know how satisfied their customers are with their service. They printed an internet link to a survey on every receipt, and 150 of their customers chose to answer the survey. The data showed that 60% of the customers were satisfied with their service. Based on this data, which of the following conclusions are valid? Choose 1 answer: A. 60% of customers in this sample are satisfied, but we cannot conclude anything about the population. B. About 60% of all Read and Feed customers are satisfied. C. About 60% of all Read and Feed customers who have internet access are satisfied.

A. 60% of customers in this sample are satisfied, but we cannot conclude anything about the population.

Sweet Treats candy company wants to introduce a new flavor of jelly bean. They have three choices: Mango, Papaya, or Coconut. They decide to do a survey to determine which flavor their customers prefer. A random sample of 100 Sweet Treats customers tried a free sample of all three flavors. The data showed that 55% percent preferred Mango, 20% percent preferred Papaya, and 25% percent preferred Coconut. Based on this date, which of the following conclusions are valid? Choose 1 answer: A. 55% percent of customers in this sample prefer Mango, but we cannot conclude anything about the population. B. About 55% percent of all Sweet Treats customers prefer Mango. C. About 55% of all adults prefer mango. C.

B. About 55% percent of all Sweet Treats customers prefer Mango.

Nayara wants to know the percentage of each grade level of students at her school who drive to school. She has 4 grade levels in her school. Which of the following survey methods will allow Nayara to make a valid conclusion about what percentage of each grade level of students drive to school? Choose 1 answer: A. Randomly select 48 students who drive to school and ask them their grade level. B. Randomly select 12 students from each grade level and ask whether they drive to school.

B. Randomly select 12 students from each grade level and ask whether they drive to school.

Santos wants to know what percentage of people who get married in his county knew each other in school. Which of the following survey methods will allow Santos to make a valid conclusion about the percentage of couples married in his county who knew each other in school? Choose 1 answer: A. Get a list of the 30 couples most recently married in his county, then ask them. B. Sort a list of couples married in his county into a random order, then ask the first 30 couples on the list.

B. Sort a list of couples married in his county into a random order, then ask the first 30 couples on the list.

Lincoln Junior High School asked all of their eighth grade students the question, "What is your favorite breakfast?" and 18%, percent answered "pancakes." Based on this data, which of the following conclusions are valid? Choose 1 answer: A. 18% percent of all students in the eighth grade at Lincoln Junior High School have pancakes as their favorite breakfast, but we cannot conclude anything about the percent of the population who have breakfast as their favorite meal. B. 18% of all students in the eighth grade at Lincoln Junior High School have breakfast as their favorite meal. C. 18% of all students at Lincoln High School have breakfast as their favorite meal.

A. 18% percent of all students in the eighth grade at Lincoln Junior High School have pancakes as their favorite breakfast, but we cannot conclude anything about the percent of the population who have breakfast as their favorite meal.

Good Taste Food Company asked 100 randomly selected students at Ridgemont High School the question, "Do you prefer pizza or a veggie burger for lunch?" and 67% percent answered "pizza." Based on this data, which of the following conclusions are valid? Choose 1 answer: A. About 67% of the students of all students at Ridgemont High prefer pizza for lunch. B. 67% of the students in the sample prefer pizza for lunch, but we cannot conclude anything about the population. C. About 67% of all teenagers prefer pizza for lunch.

A. About 67% of the students of all students at Ridgemont High prefer pizza for lunch.

Bella wants to conduct a survey to determine how many of the residents of Forks believe in supernatural creatures. Which of the following survey methods will allow Bella to make a valid conclusion about the percentage of residents of Forks that believe in supernatural creatures? Choose 1 answer: A. Ask a randomly selected sample of residents to answer the question anonymously. B. Ask a randomly selected sample of high school students to answer the question anonymously.

A. Ask a randomly selected sample of residents to answer the question anonymously.

The drama teacher wants to know whether more families of students at the school would attend a musical or a comedy. Which of the following survey methods will allow the drama teacher to make a valid conclusion about which genre of performance more families would attend? Choose 1 answer: A. Assign a number to each family, use a computer program to select 20 random numbers between 1 and the total number of families, and ask the families selected. B. For each letter of the alphabet, assign a number to each family whose last name begins with that letter, use a computer program to select a random number between 1 and the total number of families whose last name begins with that letter, and ask the family selected.

A. Assign a number to each family, use a computer program to select 20 random numbers between 1 and the total number of families, and ask the families selected.

The school board administered a math test to all students in grade 6 at High Achievers Charter School and determined that 15%, percent of them were below grade level in math. Based on this data, which of the following conclusions are valid? Choose 1 answer: A. 15% of students in the sample are below grade level in math, but we cannot conclude anything about the students in grade 6 at HACS. B. 15% of all students in grade 6 at HACS are below level in math. C. 15% of all students at HACS are below grade level in math.

B. 15% of all students in grade 6 at HACS are below level in math.

Wholesome Food Company has been hired to design a healthy menu for the cafeteria at Ridgemont High School. They want to conduct a survey to determine what percentage of Ridgemont's 1500 students like broccoli. The survey will ask, "Do you like broccoli?" Which of the following survey methods will allow Wholesome Food Company to make a valid conclusion about the percentage of students at Ridgemont that like broccoli? Choose 1 answer: A. Ask 100 students in line at the salad bar during lunchtime for one week. B. Assign a number to each student, and use a computer program to generate 100 different random numbers between 1 and 1500. Ask those students whose numbers are selected.

B. Assign a number to each student, and use a computer program to generate 100 different random numbers between 1 and 1500. Ask those students whose numbers are selected.

Ross wants to conduct a survey of his 400 classmates to determine which candidate for class treasurer, Warren or Willa, is in the lead in the upcoming election. Ross will ask the question, "If the election were today, which candidate would get your vote?" Which of the following methods of surveying his classmates will allow Ross to make valid conclusions about which candidate is in the lead? Choose 1 answer: A. Ask the 50 students in his first and second period classes. B. Put the names of all the students in a hat, and draw 50 names. Ask those students whose names are drawn.

B. Put the names of all the students in a hat, and draw 50 names. Ask those students whose names are drawn.

Wholesome Food Company asked all students on the baseball team at Ridgemont High School the question, "Do you like broccoli?" and 15% percent answered "Yes." Based on this data, which of the following conclusions are valid? Choose 1 answer: A. 15% of all students at Ridgemont High like broccoli. B. 15% of the outfielders on the baseball team like broccoli, but we cannot conclude anything about the population. C. 15% of all students on the baseball team at Ridgemont High like broccoli.

C. 15% of all students on the baseball team at Ridgemont High like broccoli.

When Jonas becomes the Receiver of Memory, he gets a rule that he may not tell his dreams. He wants to know how many of his 50 classmates have the same rule. He asks 5 friends from his class whether they may tell their dreams. Of those, 4 say that they may. Based on this data, which of the following conclusions are valid? Choose 1 answer: A. About 80% of all of Jonas's classmates may tell their dreams. B. About 80% of all people in Jonas's community may tell their dreams. C. 80% of the classmates in this sample may tell their dreams, but we cannot conclude anything about the population.

C. 80% of the classmates in this sample may tell their dreams, but we cannot conclude anything about the population.