Question 41 (2 points)

Consider the quadratic function y = ax² + bx + c . This function has

Question 41 options:

two real roots if b² < 4acan inverse U shape if b > 0 and is symmetrical around a vertical line through its maximuman inverse U shape if a > 0 and is symmetrical around a vertical line through its maximuma U shape if b > 0 and is symmetrical around a vertical line through its minimuma U shape if a > 0 and is symmetrical around a vertical line through its minimum

Question 42 (2 points)

The following output shows multiple regression results for Sales as a function of Price and Advertising expenditures. Answer this question using this output.

The regression equation is Sales = - 54.8 - 0.0676 Price + 0.215 Adver

Predictor CoefSE CoefTPConstant -54.8012.30-4.460.000Price -0.067630.04762-1.420.171Adver 0.215190.029697.250.000S = 3.760

Analysis of Variance

SourceDFSSMSFPRegression2844.05422.0329.850.000Residual Error20282.7514.14Total221126.80

If asked whether the entire model explains a significant amount of variation in Sales at the .01 level, you would say

Question 42 options:

yes, because the standard error of estimate is only 3.760yes, because the p value in the Analysis of Variance table is smaller than .01no, because the Total SS is over 1,000no, because one coefficient in the model is significantly different from zero and the other is not at the .01 levelno, because the large F value indicates a large amount of residual variation in Sales

Question 43 (2 points)

A disease afflicts one person per hundred in a certain population. A test for the disease has false positives of 5%, and false negatives of 2%. A random person from the population tests positive for the disease. What is the approximate probability that the person truly has the disease?

Question 43 options:

.95.11.07.17.98

Question 44 (2 points)

You make an investment of $100. The investment will be compounded continuously (i.e., instantaneously) at the rate .05 per year. How long (approximately) will it take for your investment to triple in value?

Question 44 options:

10 years22 years14 years7 years30 years

Question 45 (2 points)

Assume that X is a binomial random variable and Y is a Poisson random variable. Then,

Question 45 options:

X measures the number of times an event occurs in n Bernoulli trials and Y measures the number of times an event occurs within a period of timeboth X and Y are examples of discrete random variablesX is a discrete random variable but Y is a continuous random variableboth a and b are correct answers but c is incorrectboth a and c are correct answers but b is incorrect