Statistics and Probability (a review)

Statistics and Probability (a review)

By Katie Butler

Poll

How are you feeling today?

• Great!

• So-so

• Could be better...

• Having a tough day.

Multiple Select

What is random sampling? (Choose all that apply)

• A sampling method that favors a certain group over another

• A sampling method where each member of the population has an equal chance of being selected

• Sampling method used to avoid bias and other unwanted effects

Random Sample

*Each member of the population has an equal chance of being selected

*Used to avoid bias and other unwanted effects

Multiple Choice

Open the image and select the best answer.

• A

• B

• C

• D

Multiple Choice

Open the image and select the best answer.

• A

• B

• C

• D

Multiple Choice

Open the image and select the best answer.

• A

• B

• C

• D

Liklihood of events

• Impossible

• Unlikely

• Equally likely

• Likely

• Certain

Multiple Choice

Open the image and select the best answer.

• A

• B

• C

• D

Population

A population is a set of people or things that we want to study.

Multiple Choice

Mrs. Greear wants to see if the students at Jenifer Middle School want to change the amount of time they get for lunch. What is the population for this question?

• Mrs. Greear

• the students at Jenifer Middle School

• lunch

• the cooks

Multiple Choice

Tony wants to find out how the 7th grade students at his school feel about the amount of homework they receive each week. What is the population for this question?

• Tony

• All the students at his school

• All the 7th grade students at his school

• All 7th graders

Sample

A sample is part of a population. Its distribution should resemble the population's distribution.

(If your population is all 7th grade students, then your sample should include all kinds of 7th grade students, not one specific group)

Multiple Choice

The owner of all the McDonald's in the Valley (there are three) wants to know if the workers at her stores are happy with the hours they work.

Which of the following strategies would produce a representative sample?

• Ask 50 random customers at each store throughout a business day.

• Select 12 random employees from each store.

• Ask all the employees from one store.

• Ask the first 8 employees that arrive to work at each store.

Multiple Choice

The McDonald's owner finds that 28 of the 36 employees surveyed are happy with the hours they work.

If McDonald's has 198 employees, how many do you predict are happy with the hours they work?

• 64

• 56

• 150

• 154

Multiple Select

The dot plots show the grades of 21 students in two different subjects.

Select all the true statements.

• The grades in History are more consistent than the grades in Math.

• The grades in both classes are equally consistent.

• The grades in Math are more consistent than the grades in History.

• The mean grade in History is higher than the mean grade in Math

• The mean grade in Math is higher than the mean grade in History.

Multiple Choice

Tony wants to find out how the 7th grade students at his school feel about the amount of homework they receive each week. What is the population for this question?

• Tony

• All the students at his school

• All the 7th grade students at his school

• All 7th graders

Multiple Choice

You randomly choose one marble from the bag. What is the theoretical probability of choosing a blue marble?

• $$\frac{6}{15}\ or\ \frac{2}{5}$$

• $$\frac{9}{15}\ or\ \frac{3}{5}$$

• $$\frac{3}{15}\ or\ \frac{1}{5}$$

Multiple Choice

What is the theoretical probability of spinning a red or a yellow?

• $$\frac{2}{5}$$

• $$\frac{1}{5}$$

• $$\frac{3}{5}$$

• $$\frac{0}{5}$$

Multiple Choice

At a middle school, the 7th graders will conduct a survey for where to go on a field trip. Which method will result in the least biased decision?

• to randomly ask 8th grade students who went on a field trip last year
• to randomly choose some 7th grade students to select a location
• to ask all 7th grade teachers and administrators for a location
• to ask the student council to choose a location

Multiple Choice

Roberto wants to know the favorite sport of adults in his hometown. He surveys 50 adults at a baseball game. Is this random or biased sampling?

• Random

• Biased

Multiple Choice

If you score 76, 85, 97, and 83 on your math tests, what would your median score be?

• 84

• 90

• 85

• 88

Multiple Choice

Which class did better on the test?

• 1st period

• 2nd period

• They both performed the same