To determine if there are outliers in a least squares regression models data set, we could construct a boxplot of the
A) residuals. B) response variables.
C) predictor variables. D) lurking variables.
Q. 2Assume that the random variable X is normally distributed, with mean = 50 and standard deviation = 16. Compute the probability P(6 < X < 70).
A) 0.8914 B) 0.8819 C) 0.8944 D) 0.7888
Q. 3The business college computing center wants to determine the proportion of business students who have personal computers (PCs) at home. If the proportion exceeds 30, then the lab will scale back a proposed enlargement of its facilities.
Suppose 300 business students were randomly sampled and 65 have PCs at home. What assumptions are necessary for this test to be satisfied? A) No assumptions are necessary.
B) The sample variance equals the population variance.
C) The population has an approximately normal distribution.
D) The sample mean equals the population mean.
Q. 4Smith is a weld inspector at a shipyard. He knows from keeping track of good and substandard welds that for the afternoon shift 5 of all welds done will be substandard.
If Smith checks 300 of the 7500 welds completed that shift, what is the probability that he will find less than 20 substandard welds? A) 0.9066 B) 0.4066 C) 0.0934 D) 0.5934
Q. 5Assume that the random variable X is normally distributed, with mean = 100 and standard deviation = 15. Compute the probability P(X > 112).
A) 0.2119 B) 0.1977 C) 0.7881 D) 0.2420
Q. 6According to the Federal Communications Commission, 70 of all U.S. households have vcrs. In a random sample of 15 households, what is the probability that the number of households with vcrs is between 10 and 12, inclusive?
A) 0.5947 B) 0.4053 C) 0.7 D) 0.2061
Q. 7True or False: If a residual plot shows an almost straight line then a linear model is appropriate.
A) False B) True
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