博客

HW 1: Review of (parts of) stats 516 and introduction to R.

r语言作业代做 or problems 3-7, use the distribution tables in the appendix of the 525 textbook. For problems 7 11, use R. Look at the R links on the···

r语言作业代做

For problems 3-7, use the distribution tables in the appendix of the 525 textbook. For problems 7 11, use R. Look at the R links on the class Moodle page to learn how to download R and RStudio. For problems 8-12, and future relevant HW problems, you must submit your R code along with your answers. You must also document (explain) your code with internal comments and use meaningful/clear names for your variables. The code will be graded, not just on correctness, but also on understandability/presentation. (Think of this as analogous to writing. Later in life, not only will you need to come up with ideas on how to tackle problems, but you will need to be able to effectively communicate the ideas to your colleagues.) If the presentation of the code is too poor, it will be automatically graded as incorrect.

r语言作业代做

1. Readthe academic honesty section on our Moodle  Explain what it means to you. Also answer the following. If someone asks for help on a homework problem, what can you do? What is the dividing line between something you do not need to cite and something you do need to cite in your IE final project (give examples)? If person A told you that person B cheated in some way, what should you do?
2. Ifyou have not already done so do the following activities: download R and RStudio; visit a Limnu board; sign up for this classes Piazza forum; read through the Moodle course page. Once you have done this, write the sentence “I certify that I have read and visited the online sites mentioned in this question.” Answer the following questions: how many quizzes will there be? what are the dates mentioned in the IE project? how will your participation grade be determined?
3. A UMass Bio 101 student counts the number of hairs in 8 (sedated) squirrels’ tails and comes up with the following:

3005 2925 2935 2965 2995 3005 2937 2905  r语言作业代做

Assume that UMass squirrel tail haircounts are normally distributed.

• Finda 95% confidence interval for the true average µ of UMass squirrel tail  Write a sentence interpreting what you found.
• TheBio 101 professor claims that squirrel tail haircounts averages are not less than  Do the sample data provide sufficient evidence to contradict the professor’s claim at .025 level of significance?  Depending on the book, instructor, example, etc, sometimes we refer to the test’s “level of significance,” “α-level,” “α-level of significance” or just “level.” These mean the same thing: the probability of committing a Type-1 error is .025.
• Whatis the p-value? Some books call this the “attained significance ” I’ll try to avoid this because of possible confusion with the other terms. Recall that when you use tables, it suffices to just give the smallest range (determined from the table) in which the p-value lies. But when you use R, you will get the p-value exactly (up to rounding).

4. To reach maximum efficiency in performing an assembly operation in a manufacturing plant,new employees require approximately a 1-month training  A new method of training was suggested, and a test was conducted to compare the new method with the statistical procedure. Two groups of nine new employees each were trained for a period of 3 weeks, one group using the new method and the other following the standard training procedure. The length of time (in minutes) required for each employee to assemble the device was recorded at the end of the 3-week period. The resulting measurements are as shown in the following:

Assume that the assembly times are normally distributed, that the variances of the assem- bly times are equal for the two methods, and the samples are independent.

• Estimatethe true mean difference (µ₁ − µ₂), with confidence coefficient .95. Explain if you can tell whether or not one procedure differs from the
• Isthere sufficient evidence to indicate a difference in true mean times for the two methods? Test at α = .05 level of

5. Acompany produces machined engine parts that are supposed to have a diameter variance no larger than .0002 (diameters measured in inches). A random sample of 10 parts gave a sample variance of .0003. Assume that the 10 measurements are normally distributed.

• Testat the 5% significance level, H₀ : σ² = .0002  H_A : σ² > .0002.
• Determinethe p–

6. Suppose that we wish to compare the variation in diameters of parts produced by the companyin the previous question with the variation in diameters of parts produced bya competitor. Recall the sample variance for our company was s²= .0003. Note that

the sample variance of the diameter measurements for 20 of the competitor’s parts was.0001(=s²).

r语言作业代做

• Dothe data provide sufficient information to indicate a smaller variation in diameters for the competitor? Test at the 5% α-level.
• Determinethe p–

7. Anexperimenter wanted to check the variability of measurements obtained by using equip- ment designed to measure the volume of an audio source. Three independent measurements recorded by this equipment for the same sound were 1, 5.2 and 10.2. Assume that these measurements are normally distributed. Estimate the population variance of measurements σ² with confidence coefficient .90 and interpret it.
8. (a)Write an R code to obtain a 90% confidence interval for µ when the sample size is

n = 323, the sample mean is y¯ = 4.21, and the sample standard deviation is s = 1.21.

(b) Simulate 1, 000 draws from the sampling distribution of Y¯ . Plot a histogram of Y¯

r语言作业代做

on the density scale. Add vertical lines at Y¯and the upper and lower bounds of the interval derived in (a), and overlay the density of the sampling distribution of Y¯ on the histogram.

9. Write an R code to choose between the alternatives H₀: µ = 4 and H_A : µ < 4, where α-level is 03 and n = 100, y¯ = 3.92, s = 6.57. Do this seeing where the test lies in relation to the rejection region. Also compute the p-value and see if this is consistent with your decision.
10. Writean R code to choose between the alternatives H₀ : µ = —10 and H_A : µ /= —10 where the α level is 0.15 and n = 13, y¯ = —6.81, s = 1.55. Do this seeing where the test lies in relation to the rejection  Also compute the p-value and see if this is consistent with your decision.
11. Writean R code to obtain a 95 percent confidence interval for µ_y — µ_x when n_y = 64, y¯ =

1.1, Σ(y_i — y¯)² = 89.76, n_x = 49, x¯ = 3.64, Σ(x_i — x¯)² = 54.63. Choose between the alternatives H₀ : µ_y = µ_x and H_A : µ_y /= µ_x with α level is 0.01. Also compute the p-value and see if this is consistent with your decision.

12. Writean R code to obtain a 85% confidence interval for σ² when n = 424, y¯ = 6.09, s = 2.78.

更多代写：X86汇编代写 生物学代考 统计学代写 apa论文  lab report怎么写 数据挖掘作业代写

合作平台：天才代写 幽灵代写  写手招聘  paper代写