A farmer wishes to test the effects of a new fertilizer on her tomato yield. She has four equal-sized plots of land-- one with sandy soil, one with rocky soil, one with clay-rich soil, and one with average soil.
She divides each of the four plots into three equal-sized portions and randomly labels them A, B, and C. The four A portions of land are treated with her old fertilizer. The four B portions are treated with the new fertilizer, and the four Cs are treated with no fertilizer. At harvest time, the tomato yield is recorded for each section of land. What type of experimental design is this? A) randomized block design B) completely randomized design
C) matched-pairs design D) double-blind design
Q. 2When performing a multiple linear regression, if we test the null hypothesis that the coefficients are all zero, what is the decision rule?
A) If p < , then reject the null hypothesis.
B) If p > , then reject the null hypothesis.
C) If p < , then fail to reject the null hypothesis.
D) If p > , then fail to reject the alternative hypothesis.
Q. 3In a random sample of 60 dog owners enrolled in obedience training, it was determined that the mean amount of money spent per owner was 109.33 per class.
Assuming the population standard deviation of the amount spent per owner is 12, construct and interpret a 95 confidence interval for the mean amount spent per owner for an obedience class. A) (106.29, 112.37); we are 95 confident that the mean amount spent per dog owner for a single
obedience class is between 106.29 and 112.37.
B) (106.78, 111.88); we are 95 confident that the mean amount spent per dog owner for a single
obedience class is between 106.78 and 111.88.
C) (106.23, 112.43); we are 95 confident that the mean amount spent per dog owner for a single
obedience class is between 106.23 and 112.43.
D) (106.74, 111.92); we are 95 confident that the mean amount spent per dog owner for a single
obedience class is between 106.74 and 111.92.
Q. 4When constructing a confidence interval about the mean response of y in a linear regression, the t-distribution is used with degrees of freedom.
A) n - 2 B) n - 1 C) n + k - 2 D) n1 + n2 - 2
Q. 5True or False: As the number of degrees of freedom increases, the chi-square distribution becomes more nearly symmetric.
A) True B) False
Q. 6License plates in a particular state display 3 letters followed by 4 numbers. How many different license plates can be manufactured? (Repetitions are allowed.)
A) 175,760,000 B) 12 C) 36 D) 260
Q. 7The number of violent crimes committed in a day possesses a distribution with a mean of 2.2 crimes per day and a standard deviation of 6 crimes per day.
A random sample of 100 days was observed, and the mean number of crimes for the sample was calculated. Describe the sampling distribution of the sample mean. A) approximately normal with mean = 2.2 and standard deviation = 0.6
B) approximately normal with mean = 2.2 and standard deviation = 6
C) shape unknown with mean = 2.2 and standard deviation = 6
D) shape unknown with mean = 2.2 and standard deviation = 0.6
Q. 8Is a confidence interval or a prediction interval the wider interval at the same level of significance?
A) Prediction Interval B) Confidence interval
Quick Reply
