Ex. p.17. Summary: a graph of a set of data pairs used to help you recognize and make.

Transcription

1 Learning Target: I can draw a best fit line on a scatter plot and use it to make predictions. p.17 Remember what a scatter plot is? a graph of a set of data pairs used to help you recognize and make. Patterns of a scatter plots What's next? 1. Make scatter plot. 2. Determine if there's a pattern/correlation. 3. If there is a pattern, draw a. 4. Use fitted line to make. Def. Fitted Line If a scatter plot has a pattern, a fitted line can be drawn to show a. A fitted line is used to make. A fitted line is drawn: > so half of the points are and the fitted line. > follows the. Ex. Does studying matter? What test score should Jordan expect if he studies for 10 hours? Summary:

2 CW p.18 (1a f) P p (all) p.18 A snack shop owner is trying to decide how much hot cocoa to make each day. The owner records the high temperatures and cocoa sales each day for two weeks. Title: 1. a. Make a scatter plot of the data. Put high temperature on the horizontal axis. b. If it makes sense to draw a fitted line, draw one. c. What kind of correlation does the scatter plot have? Explain. d. How many cups of cocoa should the owner expect to sell if the high temperature is 63 degrees? Explain or show how you got your answer. e. If the owner plans to sell about 20 cups of cocoa in one day, what is the expected high temperature for that day? Explain or show how you got your answer. f. Suppose one pot makes 10 cups of cocoa. How many pots should the owner make when the high temperature is 50 degrees?

3 2. 3. p.19 A) What kind of correlation does the scatter plot model? A) What kind of correlation does the scatter plot model? B) If there is a positive or negative correlation, draw a fitted line. C) Describe a relationship of the scatter plot. B) If there is a positive or negative correlation, draw a fitted line. C) Describe a relationship of the scatter plot. D) How many ice cream cones should the owner expect to sell if it's 80 degrees between 2 and 3pm? Show or explain how you got your answer. D) How much should you expect to pay for a car that is 7 years old? Show or explain how you got your answer. 4. A) What kind of correlation does the scatter plot model? B) If there is a positive or negative correlation, draw a fitted line. C) Describe a relationship of the scatter plot. D) Why is it not possible to use this scatter plot to make predictions of the price of hair gel based on the quantity?

4 Box 5 IF Checking: p Sketch a graph that has a positive correlation. Name two variables that have a positive correlation. Box 6 Sketch a graph that has a negative correlation. Name two variables that have a negative correlation.

5 1 3 Spaeth Spaeth Spaeth Spaeth Spaeth Spaeth Spaeth Spaeth Spaeth Spaeth Spaeth Spaeth Spaeth Spaeth

6 P p answers 1. positive as temperature increases, ice cream sales increase. 3. negative as CD sales increase, cassette sales decrease. 5. no correlation. 7. no correlation. 2. no correlation. 4. negative as car age increases, price decreases. 6. positive as hours spent reading increase, number of pages read increase. 8. negative as x increases, y decreases ab 11. 9x y t 2 + 3t x = y = 6

7 Learning Target: I can draw a best fit line on a scatter plot and use it to make predictions. p.17 Remember what a scatter plot is? a graph of a set of data pairs used to help you recognize and make. patterns predictions Patterns of a scatter plots positive corr. negative corr. no corr. What's next? 1. Make scatter plot. 2. Determine if there's a pattern/correlation. 3. If there is a pattern, draw a. 4. Use fitted line to make. fitted line. predictions Def. Fitted Line If a scatter plot has a pattern, a fitted line can be drawn to show a. A fitted line is used to make. A fitted line is drawn: > so half of the points are and below the fitted line. > follows the. pattern predictions above pattern of the data Ex. Does studying matter? What test score should Jordan expect if he studies for 10 hours?

8 Strong vs. Weak Correlation fitted line fitted line2 fitted line3

9 Ex. 1 Does studying matter?

10 Ex. 2 Does bigger TV mean watching more TV?

11 Ex. 3 Does playing too much video games waste brain cells?

12 Draw fitted lines on problems 1 8 on p.15 Are they weak or strong correlations? p.15 p (3, 6, 7, 14) p (all) 8.

13 p.16

14 Summary: A fitted line can only be drawn on scatter plots that show a pos. or neg. corr. Use fitted line to make predictions.

15 CW P p.18 (1) p (all) SHOW WORK! 1. Complete CW problems first. 2. Check answers here. 3. Raise hand ( Spaeth ) purple sheet P 4. Work on. 1 1c. negative as temp increases, cups of cocoa sold decreases. 1d. (answers will vary) about 15 cups. 1e. (answers will vary) about 60 degrees. 1f. (answers will vary) 4 pots.

16 P p answers 1. 1c. negative as temp increases, cups of cocoa sold decreases. 1d. about 15 cups. 1e. about 60 degrees. 1f. 4 pots. 2a. positive 2c. as temp increases, cones sold increases. 2d. about 35 cones 3a. negative 3c. as car age increases, the price decreases. 3d. about $2500 4a. no correlation 4c. there is no relationship between price and quantity of hair gel. 4d. there is no pattern in the data, so you cannot make valid predictions.