Stats Study Guide for Chapter 2 (Practice Test)
1. Tell which linear model is better. Justify your answer in complete sentences and use correct vocabulary words:
A. B.
Observed / Observed y / Predicted y / Errors / Errors2x
8 / 2 / 2.47 / -0.47 / 0.2209
11 / 5 / 4.051 / 0.949 / 0.900601
17 / 6 / 7.213 / -1.213 / 1.471369
19 / 9 / 8.267 / 0.733 / 0.537289
Observed / Observed y / Predicted y / Errors / Errors2
x
8 / 2 / 2 / 0 / 0
11 / 5 / 5 / 0 / 0
17 / 6 / 11 / -5 / 25
19 / 9 / 13 / -4 / 16
2. Use (8, 2) and (19, 9) to make a linear model
3. Use your model on #2 to fill in the table
Observed / Observed y / Predicted y / Errors / Errors2x
8 / 2
11 / 5
17 / 6
19 / 9
4. Use the information from #3 and #1 to explain how your model compares to the ones in #1
5. Consider the correlation between the SAT-M scores and GPA of the 1997 Psych 30 class. Here are the Math SAT scores and the GPA scores of 13 of the students in the class answer the following:
GPA / Math SAT3.40 / 640.00
3.65 / 550.00
2.90 / 640.00
2.50 / 620.00
3.07 / 440.00
2.30 / 710.00
2.75 / 600.00
3.30 / 680.00
3.40 / 560.00
3.00 / 550.00
3.70 / 680.00
3.00 / 720.00
3.10 / 575.00
a) Find the line of best fit.
b) Make a prediction for a GPA of 3.50. Is this an interpolation or extrapolation explain why?
c) Make a prediction for a GPA of 2.00. Is this an interpolation or extrapolation explain why?
d) Find the correlation coefficient.
e) What does the slope linear model in (a) mean?
6. Explain what does “Correlation does not mean causation” mean and give an example.
7. Match the scatter plot with the most appropriate correlation coefficient
r = -0.2 ____
r = 0.5 ____
r = -0.83 _____
r = - 0.99_____
r = 0.95_____
r = 0.99_____
Arrange the Scatter plots in order from weakest to stronges______,______,______,______,______,______.
8. Tell what can help you determine if a model is good for the data.
9. f(x) =3x2 +2x – 5 Evaluate: a) f(3) b) f(-2) c) f(2m+5)
10. Write the appropriate answer.
Linear Model, Exponential Growth Model, Exponential Decay Model, Quadratic Model.
A) y = 3*(5.8356)0.23x______
B) y = 5x2 – 3x +59.7 ______
C) y = 3.589x – 7.891______
D) y = 8.35*(0.2235)x______
Number of Hours After Medication was ingested (h) / Number of Milligrams per Deciliter (mg/dl) in Blood Stream (c)4 / 18.0
6 / 13.9
11. The concentrations of many medications in the human bold stream are known to decay exponentially with time. The table below gives such information about a particular medication.
a) Give an exponential model for the data.
b) From the model, estimate the initial concentration of the medication in the blood stream.
c) Estimate the concentration you would expect to find 12 hours after it was ingested.
12. Use 3 Points to graph. Find Domain and Range. If it has an asymptote draw it.
13. f(x) = -2x2+8x – 5
(a) Opens: up or down
(b) has a: max or min
(c) Vertex:
(d) Domain:
(e) Range:
(f) y-int:
(g) x-int:
(h) Graph:
14. Given the following data find a quadratic model.
x / y1 / 2
2 / 12
3 / 34