1.1) (Ch. 7) Explain what a residual is (also known as residual of prediction).
e idea of “least squares” in regression (you need to fully read pp. 200-208 to understand).
3) What does it mean if b = 0?
4) What does it mean when r-squared is 0? What does it mean when r-squared is 1?
5) What is the difference in an unstandardized regression coefficient and the standardized regression coefficient?
6) If a report says test performance was predicted by number of cups of coffee (b = .94), what does the .94 mean? Interpret this. (For every one unit increase in ___,There is an increase in ___ )
7) If F (2,344) = 340.2, p < .001, then what is this saying in general about the regression model? (see p. 217)
8) Why should you be cautious in using unstandardized beta? (p. 218)
9) (Ch. 8) Explain partial correlation in your own words. In your explanation, explain how it is different from zero-order correlation (aka Pearson r).
10) (Ch. 9) What is the F statistic used to determine in multiple regression?
11) What is F when the null hypothesis is true?
12) In Table 9.4, which variable(s) are statistically significant predictors?
13) In Table 9.4, explain what it means if health motivation has b = .36 in terms of predicting number of exercise sessions per week.
14) What is the benefit of interpreting standardized beta weights? (see p. 264).
15) What happens if your predictor variables are too closely correlated?
16) Reflect on your learning. What has been the most difficult? How did you get through it? What concepts are still fuzzy to you? Is there anything you could share with me that would help me address how you learn best?
2.the girl on the sled, weighing 50 lb, leaves point A from rest and goes down a 2% icy slope
no friction). She collides with her friend, weighing 60 lb, at
point B, 140 feet down the
slope. After colliding, they travel together down the slope on the sled. The slope is maintained, but the ice is a
little rougher, with a coefficient of friction of μk = 0.20.
a) How fast will they be moving immediately after they collide?
b) Will they come to a stop after the collision? If so, how far will they travel
until they do? If not, what will their acceleration be?
7.2)Two books are accelerating to the right on a frictional surface and the coefficient of kinetic friction between the floor
ction between the floor and book is µk. Using the information given in the figure:
(a) draw free body diagrams for both the books, and also for the combined system (of mass m1+m2),
(b) find acceleration of the books along horizontal direction, and
(c) find the magnitude and direction of the force exerted by the left book on the right book.
3.A car of mass 1500-kg enters a circular path at point P and leaves at point Q (see the figure) at constant speed of 5.0m/s, and the frictional force acting on its tires is 2500-N.
a) how long it takes to reach point Q from point P, and
b) what should be the minimum value of the coefficient of static friction between the tires and the road?
4)In an elevator which is accelerating downward at 2.5ms−2 , a 25-kg block hangs from a spring attached to the ceiling of the elevator. If spring gets stretched by 0.15m, find its spring constant.
8.A block of mass m1 lies on the horizontal plane, and another block of mass m2 is on it. A
thrown through the system of pulleys shown in the figure. A load of mass M = m1 + m2 is suspended from the movable pulley. At what ratio between the masses m1 and m2 will the blocks not slide over each other if the coefficient of friction between the blocks is µ, and there is no friction between the lower block and the plane? The mass of the thread and pulleys, as well as the friction in the pulleys, should be neglected; the thread is considered unstretchable.