2606A STAT Assignment #1 DUE:
June 7th, 2007 (to be handed in during the class)
PART I : Multiple Choice Questions 1. The set of all objects or measurements under consideration in a statistical study is a: a) statistic b) population c) sample d) parameter e) data set The process of using information from a sample to draw conclusions about the entire population is called: a) sampling b) the scientific method c) statistical inference d) descriptive statistics A numerical measure that is computed to describe a characteristic of an entire population is called a) a population b) a parameter c) a statistic d) a sample A numerical measure for a sample is referred to as a) a population b) a parameter c) a statistic d) a sample Which of the following are measures of Central tendency? a) mean & standard deviation b) mean & median c) mean & range Identify the following variables as : categorical and qualitative, categorical and ranked, quantitative and discrete or quantitative and continuous. a) b) c) d) e) f) g) the number of students who get a final grade greater then 80% dress size: 3, 5, 7, 9, 11, 13, 15, 17 weight of a newborn in kg rating of a professor as: excellent, good, fair, poor mark out of 100 obtained on a statistics test letter grade obtained on a statistics test number of red cars in a parking lot
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PART II : Complete Answer Questions 7. A quality control inspector for a production process has just the obtained following measurements on the length (in cm) of 28 randomly selected dowels from the process and wants to use them to check whether the process is producing acceptable dowels. 5.39 5.44 5.42 5.61 5.53 5.47 5.62 5.63 5.07 5.29 5.34 5.26 5.57 5.46 5.55 5.34 5.30 5.36 5.79 5.75 5.29 5.10 5.68 5.58 5.27 5.85 5.65 5.50 a) Construct a stem-and-leaf display for the data and describe the shape of the distribution (is it symmetric, skewed left, skewed right, bell-shaped, etc., are there obvious outliers). b) What is the fraction of the dowels whose length is less than or equal to 5.45 cm? c) Obtain a relative frequency histogram of the data (use 6 classes, round-up the class width to 0.15 and start your first interval at 5). Describe the distribution and compare with the one in part a). d) What are the mean and median of the service times data? e) Calculat...