Suppose a 90 confidence interval for turns out to be (1000, 2100). If this interval was based on a sample of size n = 25, explain what assumptions are necessary for this interval to be valid.
A) The population must have an approximately normal distribution.
B) The sampling distribution of the sample mean must have a normal distribution.
C) The population of salaries must have an approximate t distribution.
D) The sampling distribution must be biased with 24 degrees of freedom.
Q. 2Multiple choice questions on a test that include as one of the choices none of the above are an example of what type of question?
A) closed question B) open question
C) framing question D) reader response question
Q. 3The number of traffic accidents that occur on a particular stretch of road during a month follows a Poisson distribution with a mean of 6.3.
Find the probability that the next two months will both result in five accidents each occurring on this stretch of road. A) 0.023064 B) 0.151868 C) 0.303736 D) 0.008924
Q. 4Construct a 95 confidence interval for p1 - p2. The sample statistics listed below are from independent samples. Sample statistics: n1 = 50, x1 = 35, and n2 = 60, x2 = 40
A) (-0.141, 0.208 ) B) (-0.871, 0.872 ) C) (-1.341, 1.781 ) D) (-2.391, 3.112 )
Q. 5Which of the following is not a characteristic of Students t-distribution?
A) mean of 1
B) symmetric distribution
C) depends on degrees of freedom.
D) For large samples, the t and z distributions are nearly equivalent.
Q. 6A bag contains 10 white, 12 blue, 13 red, 7 yellow, and 8 green wooded balls. A ball is selected from the bag and kept. You then draw a second ball and keep it also.
What is the probability of selecting one white ball and one blue ball? Round your answer to four decimal places. A) 0.0490 B) 0.0480 C) 0.0090 D) 0.0088
Q. 7A researcher wants to study the effects of advertising by female models upon high school boys in small Midwestern towns. The research methodology calls for selecting several small Midwestern towns that have high schools.
What is the frame for this study? A) all high school boys from small Midwestern towns
B) all students attending high school from small Midwestern towns
C) high school boys from the small Midwestern towns selected
D) high school students from the small Midwestern towns selected
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