QNT 275T Week 5 Case Study

1) In a simple regression analysis for a given data set, if the null hypothesis β = 0 is rejected, then the null hypothesis ρ = 0 is also rejected. This statement is ___________ true.

❏ always

❏ never

❏ Sometimes

2) For a given data set, value of X, and confidence level, if all the other factors are constant, the confidence interval for the mean value of Y will ___________ be wider than the corresponding prediction interval for the individual value of Y.

❏ always

❏ sometimes

❏ never

3) Suppose that the unadjusted seasonal factor for the month of April is 1.10. The sum of the 12 months’ unadjusted seasonal factor values is 12.18. The normalized (adjusted) seasonal factor value for April

❏ is larger than 1.1.

❏ is smaller than 1.1.

❏ is equal to 1.1.

❏ cannot be determined with the information provided.

4) The simple linear regression (least squares method) minimizes

❏ the explained variation.

❏ SSyy.

❏ total variation.

❏ SSxx.

❏ SSE.

5) The correlation coefficient may assume any value between

❏ 0 and 1.

❏ −∞ and ∞.

❏ 0 and 8.

❏ −1 and 1.

❏ −1 and 0.

6) While a binomial distribution describes count data that can be classified into one of two mutually exclusive categories, a __________________ distribution describes count data that are classified into more than two mutually exclusive categories.

❏ normal

❏ skewed

❏ uniform

❏ Multinomial

7) The chi-square goodness-of-fit test for multinomial probabilities with 5 categories has _____ degrees of freedom.

❏ 5

❏ 4

❏ 3

❏ 6

8) When we carry out a chi-square test of independence, the alternate hypothesis states that the two relevant classifications

❏ are mutually exclusive.

❏ form a contingency table with r rows and c columns.

❏ have (r − 1)(c − 1) degrees of freedom.

❏ are statistically dependent.

❏ are normally distributed.

9) If the Durbin-Watson statistic is greater than (4 − dL), then we conclude that

❏ there is significant positive autocorrelation.

❏ there is significant negative autocorrelation.

❏ there is significant autocorrelation, but we cannot identify whether it is positive or negative.

❏ the test result is inconclusive.

10) The demand for a product for the last six years has been 15, 15, 17, 18, 20, and 19. The manager wants to predict the demand for this time series using the following simple linear trend equation: trt = 12 + 2t. What are the forecast errors for the 5th and 6th years?

❏ 0, −3

❏ 0, +3

❏ +2, +5

❏ −2, −5

❏ −1, −4