Inequalities
Probability
Making Inferences from Random Samples
Random Samples
100
Jake has $25 to spend at the book fair. He wants to buy a science book that costs $13 and some bookmarks that cost $2 each. What is the maximum amount of bookmarks Jake can buy? Write your solution as an inequality.
b <= 6 bookmarks
100
What is the probability of rolling an even number on a number cube?
3/6 or 1/2
100
James is buying drinks for the 7th grade party. He randomly sampled students to determine which drink they would like to have. Out of the 15 students, 3 of them chose lemonade. There are 150 students in the 7th grade. How many students should James estimate would like to have lemonade?
30 students
100
Carla has a list of 720 students in her middle school. She writes the name of each student on a slip of paper and puts each slip in a box. Then she pulls out 30 names from the box to decide who she will survey about the upcoming school election.
What is her sample size?
30 students
200
Helen babysits and wants to save at least $100 by the end of the summer. She has already saved $27. She earns $8 per hour babysitting. What is the minimum number of hours she needs to babysit to earn at least $100?
Helen must babysit at least 9.125 hours.
200
Karla has a bag of 8 red, 4 purple and 3 green marbles. What is the probability of Karla drawing out a blue marble?
0; Impossible; 0%
200
C.
200
Carla has a list of 720 students in her middle school. She writes the name of each student on a slip of paper and puts each slip in a box. Then she pulls out 30 names from the box to decide who she will survey about the upcoming school election.
How many students are in the population?
720 students
300
Valerie wants to save more than $75 to spend on her vacation. She has already saved $38 and she earns $2 per case of aluminum cans she recycles. To reach her goal, what is the minimum number of cases of aluminum cans must Valerie recycle?
Valerie must recycle more than 19 cases of aluminum cans.
300
What is the probability of not rolling a 2 or a 4 on a number cube labeled 1-6?
A. 0.33
B. 0.67
C. 0.50
D. 0.75
B.
300
Val asked a random sample of 50 students at her school if they brought lunch from home today. If 30 answered "yes", about what percentage of students at Val's school brought their lunch?
60%
300
Collin did a survey of favorite subjects. The results are below.
Subject: Number of Students:
Math 15
Science 20
ELA 10
SS 5
If there are 400 students at Collin's school, how many would you predict prefer ELA?
80 students
400
Solve the inequality:
-0.5x + 2.4 < 6.4
x > -8
400
Lynn and her mother are playing a board game. The spinner has 4 equal sections with a different color: red, green, blue, and yellow. What is the probability that Lynn will spin a blue? Write your answer as a fraction, decimal and percent.
1/4; 0.25; 25%
400
Ms. Jennings has a mystery bag full of marbles. She said there are 100 marbles in the bag. Some are red, and all of the others are blue. Joe picks a random sample of 10 marbles from the bag without looking. Suppose Joe had 4 red marbles in his sample. How many marbles would Joe estimate are red in the bag?
40 red marbles
400
Hannah surveyed 50 of the 450 students at her high school to determine who owned a cat or a dog. In her survey she found that 8 people owned a cat, 12 people owned a dog, 10 people owned a cat and a dog, and 20 people had no pets. Based on this information, how many people in the population would you predict do not own a pet?
180 people
500
An auditorium can hold up to 157 chairs. The auditorium currently has 3 rows of 10 chairs. What is the greatest number of additional rows of chairs that the auditorium can hold?
r <= 12 rows
500
During a soccer game Mary saves 12 out of 20 shots on the goal she is defending. Out of 200 goal shots, how many can Mary expect to save?
120 shots saved
500
Tammy was running for class president. She wanted to know if she had a good chance of winning the election, so she decided to have her friends help her with surveys.
Jonathan surveyed a random sample of 10 students from the school. 7 of them said they would vote for Tammy. If there are 230 students in the school, how many of them could Tammy expect to vote for her?
161 students
500
Mr. Callahan just opened a flower shop. He took a random survey of shoppers to find out their favorite flowers and recorded the results below:
Daffodil-14
Lily-10
Rose-24
Daisy-12
What is the sample size?
60 people