Warm Up Find the roots: 𝑥−3 4𝑥 2 +64 =0 2. Convert to radians I can determine if a question is biased and determine is a sample is representative Warm Up Find the roots: 𝑥−3 4𝑥 2 +64 =0 2. Convert to radians a) 125° b) 98° c) 342° 3. For what value(s) of 𝜃 is 𝑐𝑜𝑠𝜃=−.5736?

Find the roots: 𝑥−3 4𝑥 2 +64 =0 𝑥−3=0 4 𝑥 2 +64=0 𝑥=3 4 𝑥 2 =−64 𝑥 2 =−16 𝑥=± −16 𝑥=±4𝑖

2. Convert to radians a) 125° b) 98° c) 342° 25𝜋 36 49𝜋 90 19𝜋 10 𝜋 180 25𝜋 36 49𝜋 90 19𝜋 10

𝜃 is the reference angle, 55° For what value(s) of 𝜃 is cos𝜃=−.5736? 𝑐𝑜𝑠 −1 −.5736 =125° Cosine is also negative in quadrant…. Three 180+𝜃 180+55 235° 𝜃 is the reference angle, 55°

Homework Questions Check your answer on the white board. Make a note of what you want to go over next class

Polling Data Without talking to anyone, answer the questions on the poll you are given SKIP QUESTION 2 You may write on the half sheet

Proportion of “Yes” responses Topic Poll A Proportion of “Yes” responses Poll B Do teenagers worry? Skip Question 2 Violence affects young people? Movie ratings effective? Raise teacher pay? Exercise?

Classwork Problems Turn to page 54 Working in your table groups, complete problems 6-7 through 6-11 in your notebooks.

Sample Selection We just talked about how the way a question is worded and impact the way the question is answered… How can the way a survey group is selected influence the results of a survey? Consider the survey question “Do you think teachers should assign homework every night?” If only teachers were surveyed, how might this affect the survey? What if only students were questioned?

Sample Selection - Vocab Population – The group for which you are trying to collect data Sample – A small portion of the population from which you will gather data Unbiased/ Biased sample – A sample that is/is not representative of the population Example question for biased sample: “If you poll registered democrats about which presidential nominee they plan to vote for, can your results be generalized to the entire population?”

Sample Selection Self-Selected Sample – Individuals select themselves into a group to be sampled Systematic Sample – Sample is selected randomly Convenience Sample – Sample of people who are easy to reach Random Sample – Unbiased representation of a group Example of self-selected sample: Teachers are asked to completed a survey about their work hours and are offered an incentive to complete the survey Example of Systematic sample: Given a list of people, the pollster starts with the first person and polls every 4th person on the list. Example of convenience sample: A pollster surveys people walking into Lloyd Center movie theater

Sample Selection How can the number of people surveyed affect the results? Which would result in a more useful survey about the quality of a school’s cafeteria food—a survey of 10 students eating cafeteria food, or a survey of 100 students in the hallway? Why?

Margin of Error The size of the sample can directly impact your ability to extrapolate your results to the larger population. In polling, we often see a “margin of error” which refers to the amount that is allowed for miscalculations or changes in circumstance 𝑀𝑜𝐸=± 1 𝑛

Margin of Error 𝑀𝑜𝐸=± 1 𝑛 What happens to the margin of error as your sample size increases? Can your margin of error ever be 0?

Practice WS

Finish Worksheet and any missing assignments