11. Statistical inference

a. refers to the process of drawing inferences about the sample based on the characteristics of the population. b. is the same as descriptive statistics. c. is the process of drawing inferences about the population based on the information taken from the sample. d. is the same as a census

12. The collection of all elements of interest in a particular study is.

a. the population b. the sampling c. statistical inference d. descriptive statistics

13. A portion of the population selected to represent the population is called.

a. statistical inference b. descriptive statistics c. a census d. a sample

14. Statistical studies in which researchers control variables of interest are.

a. experimental studies b. control observational studies c. nonexperimental studies d. observational studies

15. A scale that only possesses the characteristic of description and order is the:

a. Ordinal scale. b. Lickert Scale. c. Nominal scale. d. Interval scale. e. Ratio scale.

10. The age (x) and length (y) of a sample of a certain type of fish is as follows: 1.0 1.5 2.0 4.0 1.5 3.0 8.5 1.0 2.0 2.5 4.0 4.5 1.80 1.85 1.96 2.27 1.67 2.20 2.26 1.94 2.00 2.02 2.38 2.15 (a) Using R, construct a scatter plot that shows the line of regression and interpret this graph. (b) Using R, find the least squares estimates and the equation of the fitted line. (c) Using R, estimate o2.[25] Prove that the following are equivalent: a) A is a variance matrix b) A is nonnegative denite c} all the eigenvalues in the spectral decomposition ofA are nonnegative d) there exist a matrix B such that A = 33' Note: you may use the spectral decomposition theorem: For any symmetric matrix A, there exists an orthogonal matrix G and a diagonal matrix D such that A = GDG'. To compare two population means, #1 and #2, with matched samples, which of the following is correct? 0 We use two different samples and calculate fl f2. 0 The two matched sample may have two different sample means, sample variances, and sample sizes. 0 We are interested in the statistical inference of f1 f2. (9 We calculate the mean and the standard deviation for the differences from all pairs for the statistical inference. Q We use the same procedure for the inference with two independent samples